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Nylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites. Highlights: Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied.Effects of CNC and activator content on CNC‐g‐PA6 properties were studied.CNC is uniformly dispersed in PA6 with average particle size less than 1 micron.The nylon matrix was significantly strengthened by the addition of CNC.The addition of CNC significantly improved the heat resistance of the composites. [ABSTRACT FROM AUTHOR]

The thermodynamic incompatibility between the soft and hard segments of thermoplastic polyurethane (TPU) results in a microphase‐separated behavior and excellent mechanical properties. However, the effect of the chain extender on the degree of microphase separation (DMS) and the resultant mechanical properties of TPU have not been well studied because of the complex interactions between the soft and hard segments. Herein, hydroxyl‐terminated polybutadiene‐based TPUs(HTPB‐TPUs) without hydrogen bonding between the soft and hard segments are synthesized using hydroxyl‐terminated polybutadiene, toluene diisocyanate, and four different chain extenders, and the effect of the chain extender structure on DMS is analyzed experimentally using a combination of analytical techniques. Furthermore, the solubility parameters of the soft and hard segments, glass transition temperatures, and hydrogen‐bond density of the HTPB‐TPUs, are computed using all‐atom molecular dynamics simulations. The results clearly reveal that the chain extender significantly affects the DMS and thus the mechanical properties of HTPB‐TPUs. This study paves the way for studying the relationship between the structure and properties of TPU. [ABSTRACT FROM AUTHOR]

Asthma is a chronic and heterogeneous disease affecting the lungs and respiratory tract. In particular, the neutrophil subtype of asthma was described as persistent, more severe, and corticosteroid-resistant. Growing evidence suggested that nontypeable Haemophilus influenzae (NTHi) infection contributes to the development of neutrophilic asthma, exacerbating clinical symptoms and increasing the associated medical burden. In this work, arginine-grafted chitosan (CS-Arg) was ionically cross-linked with tris(2-carboxyethyl) phosphine (TCEP), and a highly-efficient antimicrobial agent, poly-ε-L-Lysine (ε-PLL), was incorporated to prepare ε-PLL/CS-Arg/TCEP (ECAT) composite nanogels. The results showed that ECAT nanogels exhibited highly effective inhibition against the proliferation of NTHi, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In addition, ECAT nanogels could effectively inhibit the formation of mucins aggregates in vitro , suggesting that the nanogel might have the potential to destroy mucin in respiratory disease. Furthermore, in the ovalbumin (OVA)/NTHi-induced Balb/c mice model of neutrophilic asthma, the number of neutrophils in the alveolar lavage fluid and the percentage of inflammatory cells in the blood were effectively reduced by exposure to tower nebulized administration of ECAT nanogels, and reversing airway hyperresponsiveness (AHR) and reducing inflammation in neutrophilic asthma mice. In conclusion, the construction of ECAT nanogels was a feasible anti-infective and anti-inflammatory therapeutic strategy, which demonstrated strong potential in the clinical treatment of neutrophilic asthma. [Display omitted] [ABSTRACT FROM AUTHOR]

Recyclability of polyurethane materials is significant to relieve environmental problems caused by damaged polymers. Inspired by plenty of self‐healing properties based on dynamic covalent bonds. A high mechanical strength and thermally reversible polyurethane adhesive are acquired through co‐polymerization of poly‐1,4‐butylene adipate glycol (PBA), soybean oil‐based polyol (MESO), and toluene diisocyanate (TDI) whose linear polymer chains are constructed by Diels–Alder reaction between furfuryl alcohol (FA) and bismaleimide (BMI), named DAPU. Further, the obtained polyurethane adhesives show great recyclability, mechanical performance (Whose tensile strength can reach 91.7 MPa), and appropriate self‐healing ability through the thermally reversible Diels–Alder covalent bonds and hydrogen bonds between urethane groups, which may pave a way for further development of recyclable materials. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, the degradability by Aspergillus niger and Aspergillus clavatus of three bio-based polyurethane (PU) foams is compared to previous degradability studies involving a Pseudomonas sp. bacterium and similar initial materials (Spontón et al. in Int. Biodet. Biodeg. 85:85–94, 2013, https://doi.org/10.1016/j.ibiod.2013.05.019). First, three new polyester-polyurethane foams were prepared from mixtures of castor oil (CO), maleated castor oil (MACO), toluene diisocyanate (TDI), and water. Then, their degradation tests were carried out in an aqueous medium, and employing the two mentioned fungi, after their isolation from the environment. From the degradation tests, the following was observed: (a) the insoluble (and slightly collapsed) foams exhibited free hydroxyl, carboxyl, and amine moieties; and (b) the water soluble (and low molar mass) compounds contained amines, carboxylic acids, and glycerol. The most degraded foam contained the highest amount of MACO, and therefore the highest concentration of hydrolytic bonds. A basic biodegradation mechanism was proposed that involves hydrolysis and oxidation reactions. [ABSTRACT FROM AUTHOR]

Considering the high toxicity of toluene diisocyanate (TDI) and the low reactivity of isophorone diisocyanate (IPDI), a low‐toxicity curing agent, dimer acid diisocyanate (DDI), was used to cross‐link HTPB elastomers and propellants. The unique long‐chain structure of DDI not only ensures the elastic modulus and tensile strength of the elastomer, but also improves the flexibility to some extent. The long flexible chains promote the segment movement, which is very important for the formation of hydrogen bonds between segments. The chemical cross‐linking network and hydrogen bonding association play a significant role in the mechanical properties of the HTPB/DDI system. The relationship between the mole ratio of ‐NCO to ‐OH (R‐value) and the mechanical properties of HTPB/DDI elastomers were also investigated. In the range of R‐value from 0.85 to 1.2, the elastic modulus and tensile strength first increase and then decrease, and the elongation at break first decreases and then increases. Under the same curing conditions, the elastic modulus and tensile strength of the HTPB/DDI propellant are similar to the HTPB/TDI propellant. For the HTPB/AP/Al propellants and HTPB/AP/RDX/Al propellants, the HTPB/DDI system has lower burning rates in the range of 5–19 MPa than the HTPB/TDI system and HTPB/IPDI system. The application of DDI can reduce the burning rates of the propellant without adding any burning rate modifiers. It is considered that DDI can replace TDI and IPDI as a new curing agent with low toxicity and moderate reactivity for HTPB systems. [ABSTRACT FROM AUTHOR]

In order to investigate the curing time of different curing agents used in casting polymer bonded explosives, Fourier transform infrared spectrometer, rotary rheometer and Shore A hardness tester were used to investigate the effects of toluene diisocyanate (TDI), dimeric acid diisocyanate (DDI) and TDI/ DDI mixed curing agent on curing rate, pot life and curing time of pouring PBX slurry. The results show that the reaction rate of HTPB with different curing agents at 55 ℃ is kTDI > kTDI/ DDI > kDDI, and the reaction follows the second-order reaction rule. For cast PBX slurry with high solid content, at a curing ratio of 1. 2 and curing temperature of 55 ℃, using TDI curing agent, suitable pot life was 4 hours, curing time was 72 hours; Using DDI curing agent, pot life can reach more than 5 hours, but its curing time was 128 hours. Using TDI/ DDI mixed curing agent, curing time is 96 hours, pot life can reach more than 5 hours, curing effect is more ideal. [ABSTRACT FROM AUTHOR]

This study was based on preparation of a new category of polyurethanes with improved glass transition temperature. Firstly, diphenylsilanediol was reacted with methylene diphenyl diisocyanate and also toluene diisocyanate in 2:1 stoichiometric ratio to prepare two different urethane diols. Then, polycondensation reactions of the obtained diols with 4,4′-dichlorodiphenyl sulfone resulted in preparation of novel poly(silyl ether-sulfone-urethane)s. Spectroscopic techniques and elemental analysis were used to wholly characterize the chemical structure of the monomers and the resulting polymers. Viscosity, solubility, thermal behavior and stability, and crystallinity of the polymers were studied and through that, structure-property relationship of the two polymers was investigated. The prepared poly(silyl ether-sulfone-urethane)s had improved glass transition temperature in comparison to conventional polyurethanes with Tg of 143–165°C. The resulted polymer from methylene diphenyl diisocyanate showed higher glass transition temperature but lower solubility (average solubility in polar solvents was 3.7 vs. 4.0 g/dL) than polymer derived from toluene diisocyanate. [ABSTRACT FROM AUTHOR]

To develop Plectranthus amboinicus extract loaded Polyurethane foam dressing for burn wound healing. Plectranthus amboinicus is traditionally used as an anti-inflammatory and wound-healing agent. Its incorporation in a PU foam dressing will offer the dual benefits of foam dressing as well as the healing potential of P. amboinicus. PU foam dressings were prepared and loaded with P. ambionicus leaf extract (PAE). The dressings were prepared with varying concentrations (0.5–2%) of extract along with Toluene diisocyanate, polypropylene glycol (PPG), and liquid paraffin. The dressings were characterized by Scanning Electron Microscopy and evaluated for Moisture Vapor Transmission Rate, absorption rate, porosity, and mechanical strength followed by in vivo burn wound-healing studies in comparison to a marketed dressing. The MVTR was found to be optimum in formulations FD2-FD4 with values ranging from 2068.06 ± 0.99 to 2095.00 ± 0.25 g/m2/day. Absorption rate was found to be between 1.27 ± 0.01, 1.31 ± 0.00, and 1.30 ± 0.02 g/cm2 for formulations FD2-FD4. Formulations FD1, FD2, FD3, FD4 showed better porosity when compared to other formulations. Formulation FD4 was further characterized by micro-CT and a porosity of 46.32% was obtained. Tensile strength measurement indicated that the selected formulations were flexible enough to withstand regular handling during dressing changes. Acute dermal irritation performed on rabbits showed no irritation, erythema, eschar, and edema. In vivo wound-healing studies performed on albino wistar rats showed that the FD4 formulation has better wound healing property. Plectranthus ambionicus-loaded PU foam dressing demonstrated promising burn wound-healing potential [ABSTRACT FROM AUTHOR]

This work describes the preparation of thermally curable benzoxazine-modified polyurethanes with pendant carboxylic acid moieties, which have potential as organic coatings with enhanced thermal stability and electrical insulation properties. Thermoplastic poly(urethane-co-benzoxazine)s (PUBs) were synthesized via the polyaddition reaction of a benzoxazine diol chain extender with isocyanate-terminated urethane oligomers made from poly(tetramethylene ether)glycol at various molecular weights, dimethylol propionic acid, and toluene diisocyanate. Spectroscopic methods were utilized to characterize the proposed structures of the starting materials and final polymeric coatings and confirmation of co-presence of urethane bonds and benzoxazine rings. The curing temperature of the cross-linked PUBs (XPUBs) was evaluated using differential scanning calorimetry analysis. A catalytic effect of free carboxylic acids was observed, resulting in a lowering of the curing temperature by up to 30 °C. The XPUBs exhibited excellent thermal stability and reduced flammability compared to common polyurethane due to the formation of phenolic cross-linked linkages. The tensile strength and modulus of the XPUBs were also improved, while the extensibility of the polymeric coatings was mostly preserved. The key parameters that determine the possible application of these materials as electrical insulator coatings were very promising. The XPUBs displayed high dielectric strength of up to 38 kV/mm, low dielectric constant of less than 3, and a dissipation factor of approximately 6. [ABSTRACT FROM AUTHOR]

Polyurethanes, an important class of polymers, are used extensively for preparing various apparel, shoesoles, etc. This paper reports that polyurethanes could be prepared conveniently after blocking the precursor molecule toluene diisocyanate (TDI)with 4-bromo-1H-pyrazole to form blocked toluene diisocyanate (TDI). The blocked adducts were characterized by FTIR, NMR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and CHNS analysis. Particularly, spectroscopic analysis was used to confirm the complete blocking. The DSC thermogram showed that the blocked adducts deblock at 238 °C, regenerating TDI and blocking agent 4-bromopyrazole. At 238 °C, regenerated TDI reacted with polyolsof different molecular weights to form polyurethane under solvent-free conditions. The polyurethanes were further characterized by FTIR, NMR, thermogravimetric analysis, differential scanning calorimetry, and contact angle study. FTIR study shows that there is no peak at 2250–2270 cm−1. So it confirms the absence of NCO peaks. Contact angle measurements of various polyurethanes showed the values in the ranges of 27–50 °C, indicating generally hydrophilic natures of samples. DSC thermogram indicates the presence of glass transition temperature of synthesized polyurethanes at − 30 to − 40 °C. Viscosity measurements of polyurethanes in chloroform at different temperatures indicated decrease in viscosity at higher temperature. [ABSTRACT FROM AUTHOR]

In this work, composites were prepared in polyurethane (PU) matrices with sawdust fibers at levels of 10, 20 and 30%. The PU was obtained using polyols, castor oil and wood tar pitch (bio-pitch), reacted with a polymeric 4,4′-diphenylmethane diisocyanate (MDI), in a ratio NCO/OH = 1:1, catalyzed by dibutyltin dilaurate. Two groups of composites were formulated: materials synthesized only with polyol castor oil (PU 0%), and those obtained with 25% bio-pitch and 75% castor oil (PU 25%). The sawdust fibers were previously modified by mercerization, followed by benzylation or reaction with toluene diisocyanate (TDI). The changes were confirmed by infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetry (TG), X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The addition of bio-pitch to the matrix caused an increase in its porosity and a decrease in density. The sawdust showed good adhesion to the matrix containing bio-pitch, which was confirmed by the increase in the mechanical properties of its composites. The water absorption results showed that the matrix composites containing bio-pitch are more hydrophobic, with greater intercrossing, which corroborates the evaluation of good fiber–matrix interaction. Vegetable pitch seems to behave as a coupling agent between the fiber and the matrix, presenting itself as a suitable polyol for the synthesis of composites from renewable sources. [ABSTRACT FROM AUTHOR]

Sustainable polymer composites (or biocomposites) based on renewable and green polymers are progressively under development in a technological paradigm shift from "just use more and more" to "convert into value-added products". Therefore, significant efforts should focus not only on their reduced environmental impact but also on maximizing their performance and broadening their application range. Herein, the bio-based blends based on Mater-Bi bio-plastic and poly(ε-caprolactone), at a weight ratio of 70:30, were developed, followed by the addition of UFC100 cellulose filler to yield sustainable biocomposites. The effects of cellulose chemical modification with three diisocyanates, i.e., hexamethylene diisocyanate (HDI), methylene diphenyl isocyanate (MDI), or toluene diisocyanate (TDI) on the surface properties of biocomposites were evaluated by water contact angle and surface roughness detected by atomic force microscopy (AFM). Biocomposites containing cellulose modified with HDI, MDI, or TDI revealed contact angle values of 93.5°, 97.7°, and 92.4°, respectively, compared to 88.5° for reference blend, indicating an enlarged hydrophobicity window. This action was further confirmed by increased fracture surface roughness and miscibility detected by microscopic observation (scanning electron microscopy (SEM) and AFM). An in-depth oscillatory rheological evaluation has identified MDI, followed by TDI, as the most efficient compatibilizer of the analyzed system. Correspondingly, thermogravimetric analysis and differential scanning calorimetry analyses showed more residue and higher melting temperatures for biocomposites, more promisingly with MDI and TDI modifiers. In conclusion, either incorporation or diisocyanate modification of cellulose affects both surface and bulk properties, providing vital insights into future developments in the field. Proper selection of diisocyanate modifier of cellulose may enable engineering of composites performance. [ABSTRACT FROM AUTHOR]

This paper evaluated the effect of a biobased polyurethane modifier on the moisture resistance of asphalt binder. Biomodifiers with high acid values have been implicated in moisture damage to asphalt. Here, castor oil with a relatively high acid value of 190 mg KOH·g−1 was used to produce biobased polyurethane. Biobased polyurethane was produced by combining castor oil, toluene diisocyanate (TDI), and diethylene glycol (DEG) at a molar ratio of 1∶2∶1. Asphalt binder was modified with 3%, 6%, or 9% of the biobased polyurethane (by weight of asphalt binder), and the moisture susceptibility of the modified asphalt was evaluated with a comprehensive laboratory experiment plan using the boiling water test, the indirect tensile strength test, the bitumen bond strength test, the water contact-angle moisture-susceptibility test, and the moisture-induced shear-thinning index test. Study results showed that the introduction of biobased polyurethane enhanced the bond between the aggregate and asphalt, thereby increasing the asphalt mixture's resistance to moisture damage. Consequently, the resistance of asphalt binders to cohesive failure and adhesive failure was enhanced in biobased polyurethane, as evidenced by respective increases of 19%, 40%, and 49% in tensile strength ratio for dosages of 3%, 6%, and 9% biobased polyurethane. Compared with neat asphalt, the asphalt blend containing 9% polyurethane had the highest bond-strength increases, 55.73% and 37.93%, for dry and wet conditions, respectively. This improvement is attributable to the phenol and amide components in biobased polyurethane, which increase the polarity of asphalt binder and increase the affinity of asphalt binder to siliceous aggregate. In addition, the moisture-induced shear-thinning index and the contact-angle moisture-susceptibility index showed that increased doses of biobased polyurethane resulted in increased resistance of asphalt to moisture damage. The study outcomes promote the sustainability of asphalt construction by introducing biobased polyurethane as a sustainable modifier for asphalt. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics (2097-2806) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bio-polyols (BPOs), characterized by a hydroxyl number up to around 90 mg KOH/g, narrow polydispersity index and relatively low molecular mass up to 2000 g/mol, were synthetized from partially and completely epoxidized soybean and linseed oils and caprylic acid or 3-phenyl butyric acid. These BPOs were used in the presence of toluene diisocyanate to produce polyurethane (PU) foams by using a quasi-prepolymer method involving a two-step reaction. A detailed structural investigation of the prepolymers from toluene diisocyanate and both BPOs and polypropylene glycol was conducted by SEC and solution NMR. The apparent density of the foams was in the range of 40–90 kg/m3, with higher values for foams from the aromatic acid. All the foams showed an open-cell structure with uniform and regular shape and uniform size. The specific Young's moduli and compression deflection values suggest superior mechanical properties than the reference foams. The novel synthesized polyurethanes are excellent candidates to partially replace petroleum-based materials. [ABSTRACT FROM AUTHOR]

The synthesis of isocyanate-terminated polyurethane prepolymers was carried out by reacting toluene diisocyanate (TDI) with an acrylic polyol, PEG-400, and PEG-1000, followed by capping the prepolymers with 2-hydroxyethyl methacrylate (HEMA) to produce polyurethane acrylates. The purpose of this study was to examine how different molecular masses of PEG and HEMA impact the thermal, morphological, and hydrophilic/hydrophobic properties of PUA films. The properties of the polyurethane acrylates were analyzed using various techniques, including DSC, FTIR, TGA, 1H NMR, SEM methods, and water contact angles and gloss tests. The results indicated that microphase separation morphology is prevalent within the PUA containing PEG-1000 and that the hydrophilicity of the PUA film is primarily influenced by the microphase separation behavior. The results revealed that the addition of PEG-400 improved the compatibility of hard and soft segments, leading to a shift toward phase mixing in the microphase separation behavior of PU acrylates. The microphase separation behavior was further studied using FTIR analysis of the C = O stretching vibration, with deconvolution performed using Origin software. The findings provide valuable insights into the structure–property relationships of PU acrylates, which can be utilized to optimize their performance for different applications. [ABSTRACT FROM AUTHOR]

Exposure to toluene diisocyanate (TDI) can cause pulmonary diseases such as asthma. Inhibition of high mobility group box 1 protein (HMGB1) has been found to be protective against the toxic effects of TDI on human bronchial epithelial (HBE) cells. Here, we evaluated the in vivo positive roles of HMGB1 in the TDI-caused asthma mice and explored its underlying mechanisms in HBE cells. We found that suppression of HMGB1 obviously alleviated airway inflammation, airway hyperresponsiveness, and airway remodeling in the lung tissue of the asthma mice. The in vitro results showed that inhibition of HMGB1 ameliorated TDI-induced reactive oxygen species (ROS) release, inflammatory response, and activation of autophagy in HBE cells. At the molecular level, inhibition of HMGB1 decreased the expressions of HMGB1, Toll-like receptor 4, Vimentin and matrix metalloproteinase-9 proteins, activated NF-κB and NOD-like receptor protein 3 (NLRP3) inflammasome, and increased E-cadherin expression. Importantly, activation of autophagy could lead to the overactivation of NLRP3 inflammasome in TDI-induced asthma. These results suggest that inhibition of HMGB1 can alleviate TDI-induced asthma through ROS/AMPK/autophagy pathways, which may provide valuable evidence for the pathogenesis and therapeutic targets of TDI-induced asthma.

A series of polyurethanes (PU) were synthesised via one-step polymerisation without a chain extender, using toluene diisocyanate as well as a variety of soft segments composed of different macrodiols. Poly(D,L-lactide) (PDLLA) and polycaprolactone diol (PCL) were synthesised as a polyester type polyols to obtain soft segments. The process of varying the molar ratio of newly synthesised PDLLA in soft segments has been confirmed as a powerful tool for fine-tuning the final properties of PU. Fourier-transformed infrared spectroscopy was used for evaluation of molecular structures of synthesised PDLLA polyol and final PU. Nuclear magnetic resonance spectrometry was used to confirm the presumed structure of PU. The influence of soft segment composition on polyurethane thermal characteristics was examined using thermogravimetric analysis and differential scanning calorimetry. The composition of soft segments had little impact on the thermal stability of PU materials, which is explained by the comparable structures of both polyester polyols. Wide-angle X-ray scattering was utilised to evaluate the effect of amorphous PDLLA on the degree of crystallinity of PCL in soft PU segments. It was discovered that not only did the PDLLA ratio in the soft segment have a substantial influence on the degree of microphase separation in the soft and hard segments, but it also influenced the crystallisation behaviour of the materials. Furthermore, the restriction of crystallisation of the PCL soft segment has been verified to be dependent on the hard segment concentration and the ratio of PDLLA/PCL polyols. The sample with pure PCL as the polyol component achieved the highest degree of crystallinity (34.8%). The results demonstrated that the composition of soft segments directly affected the properties of obtained polyurethane films. These results can be utilised to easily achieve a desirable set of properties required for application in biomaterials. [ABSTRACT FROM AUTHOR]

In this work, glycerol was chemically modified into novel toluene diisocyanate (TDI) based trifunctional polyol (NTP) by a two step process, involving the reaction of TDI with glycerol to form an isocyanate-terminated pre-polymer, followed by the reaction with glycol. A thermal and mechanical property of water-blown rigid polyurethane foam (WB-PUF) was enhanced by the partial substitution (30 & 50 wt%) of castor oil with glycerol or synthesized NTP. The effects of glycerol content and NTP on the WB-PUF properties were investigated using various characterization techniques including ATR-FTIR, TGA, SEM, compression test, and Shore-A hardness test. Notably, the introduction of NTP substitution into the formulation of WB-PUF foams had beneficial impact on the structure of materials enhancing foam density from 77 kg/m3 to 117 kg/m3 and also exhibited superior thermal and mechanical properties compared to those with glycerol and unmodified foams. Shore A hardness and compression strength of those foams ranged from 50 to 69.5 °Sh A and 1.88-3.28 MPa, respectively. These findings suggest potential applications of the modified WB-PUF in areas such as rigid tissue engineering. Graphical Abstract [ABSTRACT FROM AUTHOR]

The flow behaviour of 4‐(Dimethylsilyl) butyl ferrocene‐grafted HTPB‐based composite propellant (P01) and basic aluminized HTPB‐based propellant (P02) was investigated using shear rheometer. The experimental data were fitted to 'power law' for non‐Newtonian fluid flow, and the rheological parameters were expressed as consistency index (k) and pseudoplasticity index (n). For both the propellant compositions, a shear thinning nature (pseudoplasticity index; n < 1) has been observed. The study categorically showed that the incorporation of 4‐(Dimethylsilyl) butyl ferrocene‐grafted HTPB has resulted in increased consistency index (k) and yield stress as compared to HTPB based compositions. In addition, the time–temperature cure‐kinetics study suggested that the rate of curing reaction is higher with toluene diisocyanate as compared to isophorone diisocyanate and the Arrhenius activation energy (Ea) corroborated with the observed trend. Furthermore, the Haegen–Poisseuille equation modified for non‐Newtonian fluid flow has been employed to determine the theoretical casting rate for 4‐(Dimethylsilyl) butyl ferrocene‐grafted HTPB‐based composite propellant at different temperatures in a vacuum casting setup. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The kinetic analysis of octogen coating with a polyurethane base containing hydroxyl-terminated polybutadiene (HTPB) was investigated using infrared spectroscopy. The coating process involved a solvent method, where octogen and liquid polyurethane were mixed, the solvent was evaporated, and curing took place at an elevated temperature. The ratio of HTPB to diisocyanate was equimolar. About 200 g octogen was coated with mixture of 2 mL HTPB, 50 mL ethyl acetate, and 0.2 mL TDI in the glass beaker at 30 °C for 1 h. The filtrated ethyl acetate was then evaporated, and the residue was dried in a vacuum oven for 15 min at 30 °C. The resulting film-coated octogen was cast into a KBr pellet and cured in the oven for 7 days at 40 °C, then infrared-analyzed every hour during the curing process. After curing, the shape of the coated octogen particles was analyzed using SEM Initially, the curing process occurred in the solvent system, followed by further curing in the bulk system. The kinetic analysis was performed using a modified diffusion-autocatalytic model, which includes noncatalytic, autocatalytic, and diffusion components. This model was compared with others during the bulk reaction and proved to be effective in correcting errors, particularly in the gel time region. Thermodynamic parameters were evaluated using the Arrhenius and Eyring equations. The reaction rate was initially controlled by chemical reactivity, but after the gel time, diffusion became the controlling factor. In the HTPB-TDI system, both the noncatalytic and autocatalytic parts decreased with increasing temperature, while diffusivity increased. It is worth noting that diffusivity is temperature-dependent. Different di-isocyanates, namely toluene diisocyanate (TDI), iso-phorone diisocyanate (IPDI), and hexamethylene diisocyanate (HMDI), were studied, revealing that HMDI exhibited higher reactivity than TDI and IPDI. The catalyst effect on reaction rate of the HTPB-TDI system was investigated. The addition of catalysts (0.1%) to the HTPB-TDI system decreased their activation energy in the order DBTL > FeAA > TPB. Catalysts did not change their diffusivity. [ABSTRACT FROM AUTHOR]

In this paper, the effects of HTPBs with different main-chain microstructures on their triblock copolymers and polyurethane properties were investigated. Three polyether-modified HTPB triblock copolymers were successfully synthesized via a cationic ring-opening copolymerization reaction using three HTPBs with different microstructures prepared via three different polymerization methods as the macromolecular chain transfer agents and tetrahydrofuran (THF) and propylene oxide (PO) as the copolymerization monomers. Finally, the corresponding polyurethane elastomers were prepared using the three triblock copolymers as soft segments and toluene diisocyanate (TDI) as hard segments. The results of an analysis of the triblock copolymers showed that the triblock copolymers had lower viscosity and glass transition temperature (Tg) values as the HTPB 1,2 structure content decreased, although the effect on the thermal decomposition temperature was not significant. An analysis of the polyurethane elastomers revealed that as the content of the 1,2 structure in HTPB increased, its corresponding polyurethane elastomers showed a gradual increase in breaking strength and a gradual decrease in elongation at break. In addition, PU-1 had stronger crystallization properties compared to PU-2 and PU-3. However, the differences in the microstructures of the HTPBs did not seem to have much effect on the surface properties of the polyurethane elastomers. [ABSTRACT FROM AUTHOR]

In recent years, with the increasing consciousness on environment protection, fluorine‐free water‐repellent agents in textile industry have attracted considerable attention. Herein, we proposed a new strategy to prepare bio‐based fluorine‐free branched polyurethane@organosilicon water‐repellent agent for cotton fabric (CF). Branched polyurethane (BPU) with long alkyl chains was firstly synthesized through the reaction of glycerin monostearate extracted from natural palm fruit, toluene diisocyanate, trimethylopropane and N‐methyl diethanolamine, and then utilized to coat the C24‐28 olefin modified hydroxyl silicone oil (C24‐28 HSO) by emulsification procedure to obtain branched polyurethane@organosilicon (BPU@C24‐28 HSO) water‐repellent agent. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy confirmed the chemical structures of BPU, C24‐28 HSO and BPU@C24‐28 HSO water‐repellent agent. The biomass carbon content of the water‐repellent agent reached 54.0%. Transmission electron microscope demonstrated that the BPU@C24‐28 HSO water‐repellent agent appeared obvious spherical shape with core‐shell structure. Owing to the introduction of organosilicon, the water‐repellent agent significantly improved the softness of the CF. In addition, the CF finished by the BPU@C24‐28 HSO water‐repellent agent also exhibited excellent water‐repellent score of 90+, high water contact angle of 141.6° and superior surface stability. Our findings provided a direction to prepare environmental‐friendly and high‐performance water‐repellent agents for various fabrics. [ABSTRACT FROM AUTHOR]

In order to solve the short stabilization time of the water‐in‐oil emulsion binder system and the shortcomings of the critical blast size of the explosive ink molding sample, a water‐in‐oil emulsion binder was designed with polyvinyl alcohol (PVA) aqueous solution as the aqueous phase, fluorocarbon resin (FEVE) ethyl acetate solution as the oil phase, and toluene diisocyanate (TDI) added to modify the water‐in‐oil emulsion binder. The hexanitrohexaazaisowurtzitane(CL‐20)based explosive ink was made by incorporating submicron CL‐20 into the binder system, and the print‐formed samples were tested for microscopic morphology, crystallographic analysis, mechanical susceptibility, and detonation transmission performance. The results showed that the explosive ink's viscosity was moderate and suitable for direct printing, and the formed sample's surface particles were uniformly dispersed and had a honeycomb structure. The crystal form of CL‐20 explosive in the explosive ink did not change, the molded sample's impact and frictional sensitivities were 1 J and 32 N lower than those of submicron CL‐20, respectively, and the detonation velocity of the molded sample was 6655 m/s. The critical detonation size and critical detonation thickness were 1×0.0078 mm and 0.1 mm, respectively, and a critical detonation corner turning of 90°–160° could be achieved. The results show that the prepared binder system is stable for a long time, and the explosive ink molding samples have excellent blast transmission performance. [ABSTRACT FROM AUTHOR]

This paper aims to present the study of obtaining a potential isocyanic bonding agent. The process is based on introducing free isocyanate groups into hydantoin ring. In addition to acting as bonding agents, they can act as curing agents, promoting the formation of cross‐links with the binder so that the propellant cures. The synthesis process consisted of the reaction between toluene diisocyanate (TDI) and 5,5‐dimethylhydantoin (DMH) under different parameters (time, temperature, reaction atmosphere, solvent, and product purification). The reactions were monitored by Fourier transform infrared spectroscopy in the mid‐infrared region (FT‐IR). Furthermore, the product obtained was characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), elemental analysis (CHN), and volumetric chemistry (determination of the isocyanate‐NCO index). Changes in physical characteristics and the results of the determination of index NCO, FT‐IR, TGA, DSC, and CHN analysis indicate that the proposed reactions occurred. It is concluded that, among the parameters studied, those most suitable for the reaction system between isocyanic reagents TDI and DMH are a temperature of 90 °C, coupling of a nitrogen cylinder, and use of toluene solvent in the reaction system. [ABSTRACT FROM AUTHOR]

Polyether polyol, toluene diisocyanate, diphenylmethane diisocyanate and plasticizer were used as raw materials to synthesize the prepolymer, and polyether polyol, dimethylthiotoluene diamine (DMTDA) and MOCA were used as raw materials to synthesize the curing agent. A two-component solvent-free polyurethane waterproof coating for railway bridges with high performance and environmental protection was prepared. When the molar ratio of TDI80 and MDI50 of isocyanate was 2:1, the root index of isocyanate was 1.15, the mass ratio of polyether polyol 3050 and polyether polyol 2000 was 2:1, and the molar ratio of DMTDA and MOCA was controlled at 1:2, high performance environmentally friendly polyurethane waterproof coating for high-speed railway bridge deck with tensile strength of 6.84 MPa, elongation at break of 535% and tear strength of 35.5 N/mm was prepared. [ABSTRACT FROM AUTHOR]

Lignin isolated from agricultural residues is a promising alternative for petroleum-based polymers as feedstocks in development of antimicrobial materials. A polymer blend based on silver nanoparticles and lignin–toluene diisocyanate film (AgNPs–Lg–TDIs) was generated from organosolv lignin and silver nanoparticles (AgNPs). Lignin was isolated from Parthenium hysterophorus using acidified methanol and used to synthesize lignin capped silver nanoparticles. Lignin–toluene diisocyanate film (Lg–TDI) was prepared by treating lignin (Lg) with toluene diisocyanate (TDI) followed by solvent casting to form films. Functional groups present and thermal properties of the films were evaluated using Fourier-transform infrared spectrophotometry (FT–IR), thermal gravimetry (TGA), and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM), UV–visible spectrophotometry (UV–Vis), and Powder X-ray diffractometry (XRD) were used to assess the morphology, optical properties, and crystallinity of the films. Embedding AgNPs in the Lg–TDI films increased the thermal stability and the residual ash during thermal analysis, and the presence of powder diffraction peaks at 2θ = 20, 38, 44, 55, and 58⁰ in the films correspond to lignin and silver crystal planes (111). SEM micrographs of the films revealed the presence of AgNPs in the TDI matrix with variable sizes of between 50 to 250 nm. The doped films had a UV radiation cut-off at 400 nm as compared to that of undoped films, but they did not exhibit significant antimicrobial activity against selected microorganisms. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of sulfur dioxide (SO2) derivatives on asthma induced by ovalbumin (OVA). Sprague Dawley rats were sensitized to and challenged with OVA and SO2 derivatives (NaHSO3 and Na2SO3, 1:3 M/M) to establish 28-day (short-term) and 42-day (long-term) asthma models. Exposure to SO2 derivatives aggravated asthma and hence, promoted lung injury in OVA-induced asthma. In addition, it upregulated the protein expression of TRPV1 and downregulated the expression of tight junctions (TJs). These changes were dose-dependent and were more pronounced in the presence of a high concentration of SO2 derivatives. In vitro, SO2 derivatives also increased the calcium influx and TRPV1 protein expression, and decreased TJ expression. Besides, no significant difference in the TJ expression was found between the WT and TRPV1-/- mice. The underlying mechanism might be related to regulating the effects of TRPV1 and TJs. [ABSTRACT FROM AUTHOR]

Performing risk assessments (RA) on household use of flexible polyurethane (PU) foams requires access to reliable data about emission and migration of potential diamine impurities. A toluene diisocyanate (TDI) and a methylene diphenyl diisocyanate (MDI) based foam were thermally treated to enable measurements on samples with defined concentrations of the corresponding diamines, toluene diamine (TDA), and methylene dianiline (MDA). The thermally treated foams used for emission testing contained up to 15 mg.kg−1 of TDA and 27 mg.kg−1 of MDA. Those used for migration testing contained 5.1 mg.kg−1 of TDA and 14.1 mg.kg−1 of MDA. Stability of the thermally generated diamines was sufficient for testing over a 37-day period. Analytical techniques that did not decompose the polymer matrix were applied. Emission rates for TDA and MDA isomers were less than the limit of quantitation (LOQ) of 0.008–0.07 μg.m−2.h−1. Migration was studied using samples of the same thermally treated foams over a 35-day period. Quantifiable migration of MDA from the MDI-based foam was only observed on Days 1 and 2. From Day 3 onward, migration rates were less than the LOQ. Quantifiable migration of TDA from the TDI-based foam rapidly decreased with time and was only observed on Days 1 thru 3. From Day 4 onward, migration rates were less than the LOQ. Theoretically, the migration rate should be inversely proportional to the square root of time (t) as t−0.5. This relationship was confirmed by the experimental data and enables extrapolating migration values to more extended time periods to conduct RAs. [ABSTRACT FROM AUTHOR]

A sampling chamber was developed for emission testing of diisocyanates, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and corresponding diamines, methylene diphenyl diamine (MDA), and toluene diamine (TDA) from polyurethane (PU) product surfaces. In addition, a methodology for validation of the sampling chamber was presented, based on the introduction of generated standard atmospheres of the different diisocyanates and diamines to the sampling chamber system. Sampling of diisocyanates and diamines was performed on a circular glass fiber filter (150 mm diameter) impregnated with dihexyl amine (DHA) and acetic acid (AA) positioned inside a cylindrical stainless steel sampling chamber. The diisocyanates were immediately derivatized to DHA derivatives, and the amines were derivatized in a subsequent work-up procedure with ethyl chloroformate (ECF). The design of the sampling chamber and the presented methodology allowed for simultaneous sampling and analysis of diisocyanates and diamines of emission from a large surface area with minimal interior wall interaction in the sampling chamber. Performance characteristics of the sampling chamber for different sampling times and air humidity were obtained by determining collected amounts of the diisocyanates and diamines in the different parts of the sampling chamber. The repeatability of the collected amount on the impregnated filters in the sampling chamber was 15% with an overall recovery for 8 h of sampling in the range of 61% to 96%. The performance of the sampling chamber was not affected by air humidity (5%–75% RH), and no breakthrough during sampling was observed. LC-MS/MS determinations allowed for emission testing of diisocyanates and diamines on product surfaces as low as 10–30 ng m−2 h−1. [ABSTRACT FROM AUTHOR]

In this study, poly(thiourethane) (PTU) with different structures is synthesized by click chemistry from trimethylolpropane tris(3-mercaptopropionate) (S3) and different diisocyanates (hexamethylene diisocyanate, HDI, isophorone diisocyanate, IPDI and toluene diisocyanate, TDI). Quantitative analysis of the FTIR spectra reveals that the reaction rates between TDI and S3 are the most rapid, resulting from the combined influence of conjugation and spatial site hindrance. Moreover, the homogeneous cross-linked network of the synthesized PTUs facilitates better manageability of the shape memory effect. All three PTUs exhibit excellent shape memory properties (Rr and Rf are over 90%), and an increase in chain rigidity is observed to negatively impact the shape recovery rate and fix rate. Moreover, all three PTUs exhibit satisfactory reprocessability performance, and an increase in chain rigidity is accompanied by a greater decrease in shape memory and a smaller decrease in mechanical performance for recycled PTUs. Contact angle (<90°) and in vitro degradation results (13%/month for HDI-based PTU, 7.5%/month for IPDI-based PTU, and 8.5%/month for TDI-based PTU) indicate that PTUs can be used as long-term or medium-term biodegradable materials. The synthesized PTUs have a high potential for applications in smart response scenarios requiring specific glass transition temperatures, such as artificial muscles, soft robots, and sensors. [ABSTRACT FROM AUTHOR]

The proliferation of disposable, wearable, and implantable printable electronics requires the development of high‐performance biodegradable, and sustainable electronic components. Often green materials don't have the necessary properties for high‐performance electronics, therefore obtaining the ideal properties requires a combination of multiple green materials. A tri‐layer dielectric is reported using poly(lactic acid) (PLA), poly(vinyl alcohol)/cellulose nanocrystals (PVAc), and toluene diisocyanate terminated poly(caprolactone) (TPCL), which is integrated into semiconducting single‐walled carbon nanotube (sc‐SWCNT) based thin film transistors (TFTs) in a top gate bottom contact architecture. The PVA provides a high dielectric constant due to the hydroxy groups, the cellulose is used to optimize the viscosity, the TPCL layer provides a robust hydrophobic surface, and the PLA eliminates the interfacial charge traps present in the PVAc and improves the adhesion between PVAc and the substrate. This leads to a decrease in leakage currents and reduces the polarity at the dielectric/semiconductor interface. The TFTs fabricated using tri‐layer dielectrics led to air‐stable n‐type devices with higher overall performance when compared against the PVAc/TPCL bilayer devices. [ABSTRACT FROM AUTHOR]

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This review addresses the need for a framework to increase the consistency, objectivity and transparency in the regulatory assessment of respiratory sensitisers and associated uncertainties. Principal issues are considered and illustrated through a case study (with methyl methacrylate). In the absence of test methods validated for regulatory use, formal documentation of the weight-of-evidence for hazard classification both at the level of integration of individual studies within lines of evidence and across a broad range of data streams was agreed to be critical for such a framework. An integrated approach is proposed to include not only occupational studies and clinical evidence for the regulatory assessment of respiratory sensitisers, but also information on structure and physical and chemical factors, predictive approaches such as structure activity analysis and in vitro and in vivo mechanistic and toxicokinetic findings. A weight-of-evidence protocol, incorporating integration of these sources of data based on predefined considerations, would contribute to transparency and consistency in the outcome of the assessment. In those cases where a decision may need to be taken on the basis of occupational findings alone, conclusions should be based on transparent weighting of relevant data on the observed prevalence of occupational asthma in various studies taking into account all relevant information including the range and nature of workplace exposures to the substance of interest, co-exposure to other chemicals and study quality. [ABSTRACT FROM AUTHOR]

Toluene diisocyanate (TDI) is commonly used in manufacturing, and it is highly reactive and causes respiratory damage. This study aims to identify the mechanism of tumorigenesis in bronchial epithelial cells induced by chronic TDI exposure. In addition, transcriptome analysis results confirmed that TDI increases transforming growth factor-beta 1 (TGF-β1) expression and regulates genes associated with cancerous characteristics in bronchial cells. Our chronically TDI-exposed model exhibited elongated spindle-like morphology, a mesenchymal characteristic. Epithelial-mesenchymal transition (EMT) was evaluated following chronic TDI exposure, and EMT biomarkers increased concentration-dependently. Furthermore, our results indicated diminished cell adhesion molecules and intensified cell migration and invasion. In order to investigate the cellular regulatory mechanisms resulting from chronic TDI exposure, we focused on TGF-β1, a key factor regulated by TDI exposure. As predicted, TGF-β1 was significantly up-regulated and secreted in chronically TDI-exposed cells. In addition, SMAD2/3 was also activated considerably as it is the direct target of TGF-β1 and TGF-β1 receptors. Inhibiting TGF-β1 signaling through blocking of the TGF-β receptor attenuated EMT and cell migration in chronically TDI-exposed cells. Our results corroborate that chronic TDI exposure upregulates TGF-β1 secretion, activates TGF-β1 signal transduction, and leads to EMT and other cancer properties. [ABSTRACT FROM AUTHOR]

Hydroxyl-terminated polybutadiene/toluene diisocyanate (HTPB/TDI) system is widely used in composite solid propellants. The migrations of plasticizers and water molecules from solid propellants and surrounding environment to the inhibitor have always been the important issues. This study focuses on the preparation, characterization and anti-migration behavior of graphene oxide (GO)/HTPB nanocomposite liner. The GO/HTPB (GH) composite liners affect the migration of small molecules through a tighter cross-linked structure and weakening function of small molecule adsorption. The anti-migration performance of the liner at different temperatures was analyzed, and the influence of the added amount of GO on the anti-migration performance and adhesion performance was also systematically studied. The overall performance of the liner is optimized when the amount of GO filler is 0.3 wt%. After adding 0.3 wt % GO, the concentration of dioctyl sebacate (DOS) migrated into the liner is decreased by 23.28%, and the concentration of water molecules is decreased by 51.89%, indicating that the introduction of GO can significantly improve the anti-migration performance of the liner. In addition, the bond strength is greatly increased from 0.25 MPa to 0.95 MPa, which meets the application requirements of the current propellant system. This research provides an important way for the preparation of structure-function synergistic anti-migration composite liners. [ABSTRACT FROM AUTHOR]

Preparation of Fosthiazate (FTZ)-loaded microcapsules with controlled release was attempted by the interfacial polymerization using toluene diisocyanate (TDI) and triethylenetetramine (TETA) as monomers. The effects of the monomer concentration and the monomer concentration ratio on characteristics of the microcapsules such as size, shell thickness and release behavior in water and in soil were studied. In the study, FTZ was successfully encapsulated into a polyurea resin, and the characterization revealed that the microcapsule shell became thicker proportionally to the applied monomer concentration. The release rate of FTZ from the microcapsules in water was mostly proportional to the ratio of the surface area to the shell thickness of the microcapsules, and the release rate fitted the first-order kinetic model. On the one hand, when TDI concentration was low or the monomer concentration ratio was high, the release rate was significantly increased owing to the formation of insufficient microcapsule shell and the coarseness of the shell. Moreover, the slower the release rate in water was, the higher residual ratio of FTZ in soil could be maintained. However, it was also observed that the release rate in soil was faster than that in water. It is suggested that the constant replacement of water around the microcapsules accelerated the release rate, or the microcapsule particles migrated through the soil. These results indicated that FTZ-loaded microcapsules with controlled release were able to be prepared. In addition, basic findings about the relationship and the difference between the release behaviors of FTZ-loaded microcapsules in water and in soil were obtained. [ABSTRACT FROM AUTHOR]

To lay the foundation for environmentally friendly energetic polymer composites, GAP (glycidyl azide polymer) adhesive-based polymer films with different curing parameter R (mol ratio of hydroxyl/isocyanate) and energetic polymer composites with different RDX contents were studied. GAP/TDI (toluene diisocyanate)/GLY(glycerol) was selected as the adhesive system. The tensile strength and elongation at the break of the polymer film with R = 2.2, was 14.34 MPa and 176.86%, respectively, as observed by an AGS-J electronic universal testing machine. A relatively complete cross-linking network and high hydrogen bonding interaction were observed by LF-NMR (low-field nuclear magnetic resonance, where the cross-linking density was 11.06 × 10−4 mol/cm3) and FT-IR (fourier transform infrared spectroscopy, where the carbonyl bonding ratio was 64.84%). Forty percent RDX(hexogen) was added into the adhesive system. The tensile strength was 4.65 MPa, and the elongation at the break was 78.49%; meanwhile, the heat of the explosive was 2.87 MJ/kg, and the residue carbon rate was only 2.47%. The tensile cross-sections of energetic polymer composites were observed by SEM (Scanning electron microscopy). [ABSTRACT FROM AUTHOR]

To determine the main factors influencing dynamic pressure and large deformation roadways, a targeted set of support technologies was designed. The 2603 air inlet roadway of the Zhangcun coal mine in Lu'an, Shanxi Province, was taken as an example. The influence of the Wenwangshan South normal fault and in situ stress field on the dynamic pressure roadway was analyzed theoretically, and the main factors influencing this dynamic pressure and large deformation roadway under natural geological conditions were determined. The effect of the existing roadway support scheme was evaluated by field test methods such as nondestructive bolt testing. The influence of mining two working faces on the dynamic pressure and large deformation roadway was studied by the FLAC3D numerical simulation method. On this basis, a new grouting material was developed, a complete set of technical schemes of full-section integrated cooperative support of dynamic pressure and large deformation roadways was proposed, and the field application effect was verified. The results showed that under natural geological conditions, the 2603 air inlet roadway was located within the influence range of the Wenwangshan South normal fault, which was significantly affected and controlled by the fault. The included angle between the roadway extension direction and the maximum principal stress was 74°, which was not conducive to the stability of the roadway. The range of the roadway loose zone was large. Under the existing support conditions, the surrounding rock could not form a relatively stable structure, which was one of the main reasons for the large deformation of the surrounding rock in the dynamic pressure roadway. The 2603 air inlet roadway was affected by the mining of both the adjacent working face and the 2603 working face. The stresses were superimposed, and the roadway was greatly deformed and damaged. A new grouting material was developed. A crosslinking agent prepared by toluene diisocyanate and polyether polyol was added to the existing polyurethane material to form a new grouting material, and a complete supporting technical scheme was proposed. The field application results showed that the displacement and floor heave of both sides of the roadway were reduced by approximately 87%, the deformation and failure of the coal and rock mass of the roadway were effectively controlled, and the deformation of the dynamic pressure roadway was greatly reduced. [ABSTRACT FROM AUTHOR]

We recently used EPA databases to identify that isocyanates, most notably toluene diisocyanate (TDI), were the pollutant class with the strongest spatiotemporal and epidemiologic association with atopic dermatitis (AD). Our findings demonstrated that isocyanates like TDI disrupted lipid homeostasis and modeled benefit in commensal bacteria like Roseomonas mucosa through disrupting nitrogen fixation. However, TDI has also been established to activate transient receptor potential ankyrin 1 (TRPA1) in mice and thus could directly contribute to AD through induction of itch, rash, and psychological stress. Using cell culture and mouse models, we now demonstrate that TDI induced skin inflammation in mice as well as calcium influx in human neurons; each of these findings were dependent on TRPA1. Furthermore, TRPA1 blockade synergized with R. mucosa treatment in mice to improve TDI-independent models of AD. Finally, we show that the cellular effects of TRPA1 are related to shifting the balance of the tyrosine metabolites epinephrine and dopamine. This work provides added insight into the potential role, and therapeutic potential, or TRPA1 in the pathogenesis of AD. [ABSTRACT FROM AUTHOR]

Synthesis and characterization of novel amine terminated polybutadiene, polyurea and TiO2-nanocomposites is the aim of current art work. In this regard, polyurea synthesized trough following consecutive reactions: 1. Oxidative chains scission of polybutadiene (PB) by meta-chloroperbenzoic acid (m-CPBA) and periodic acid (H5IO6) to prepare telechelic aldehyde functionalized polybutadiene, 2. Terminal amine functionalized polybutadiene synthesis via reductive amination reaction of prepared aldehyde functionalized polybutadiene and ethylenediamine (EDA) by sodium borohydride (NaBH4) and finally, 3. Telechelic polyurea preparation through the reaction of synthesized amine functionalized polybutadiene and toluene diisocyanate (TDI). A one-pot polymerization procedure was employed to synthesize nanocomposites by the incorporation of 1 to 3% of surface modified TiO2 nanoparticles by amino propyl triethoxy silane (APTS). Successful synthesize of amine functionalized polybutadiene, polyurea and nanocomposites investigated using 1H-NMR and FT-IR spectroscopy techniques. TGA/DTG and DSC methods proved successful surface modification of nanoparticles, improved thermal stabilities with lower degradation rates and superior thermal characteristics especially in 3 wt% nanocomposite when compared by pristine sample. SEM, XRD and AFM analysis confirmed successful nanocomposite synthesis with progressed morphologic and topographic properties. [ABSTRACT FROM AUTHOR]

The siloxane-modified polyurethane oligomer (TMP) was synthesized from polyester polyol, toluene diisocyanate and 3-mercaptopropyltrimethoxysilane. The structure, thermal stability, wettability and mechanical properties of TMP were studied by Fourier transform infrared spectrometer, thermogravimetric analyzer, contact angle meter and universal tensile tester. The results show that TMP has good thermal stability and strong adhesion, and the breaking load of TMP5 on anodic alumina can reach 11 kN. At the same time, the cured TMP5 has good wettability, which provides favorable conditions for its adhesion with polyurethane sealant. [ABSTRACT FROM AUTHOR]

Spiropyran and spiroxazine photochromics have attracted increasing attention in optical data storage, optical switches, and anti-counterfeiting for decades. To expand the applications of spiropyran and spiroxazine, the durability and multi-color changes of spiropyran and spiroxazine still need to be explored. In this article, based on the subtractive principle of dyes, multi-color spiropyran and spiroxazine microcapsules with uniform particle sizes were prepared by the interfacial polymerization method via using compounds (spiropyran and spiroxazine) of different colors as the core material, and polyurethane as the shell material. Among them, toluene diisocyanate and polyethylene glycol constitute the hard and soft segments of polyurethane, respectively. The color of spiropyran and spiroxazine microcapsules can effectively switch between color and colorless, showing excellent photo fatigue resistance. The average particle size of microcapsules is 2.951 µm, and the particle distribution index value is 0.314, which shows the particle size is small and uniform. The maximum thermal decomposition temperature is 426°C, demonstrating good thermal stability. The hydrophobic photochromic fabric was prepared by coating multi-color spiropyran and spiroxazine microcapsules on cotton knitted fabric and hydrophobic treatment. The hydrophobic photochromic fabric is hydrophobic and stain resistant, and exhibits multi-color dynamic switching and long-lasting use. After 50 cycles of washing, the water contact angle of the fabric remains about 109°, showing its good washing resistance and water repellency. In addition, spiropyran and spiroxazine microcapsules are also applied in template and screen printing to impart rich and dynamic color-changing effects to fabrics, fabricating photochromic fabrics. Photochromic fabrics have potential applications in civilian and military fields. [ABSTRACT FROM AUTHOR]

Urethane-modified alkyd resins were synthesized using the depolymerization intermediates obtained from simultaneous hydrolysis–glycolysis reactions of post-consumer poly(ethylene terephthalate) (PET) bottles with dipropylene glycol (DPG) and water. For this aim, first, the synthesis of a four-component reference alkyd resin having an oil content of 50% was synthesized by using tall oil fatty acid (TOFA), trimethylolpropane (TMP), phthalic anhydride (PA), and dipropylene glycol (DPG). The PET-based alkyd resins were also synthesized using different amounts and types of purified and fractionated depolymerization intermediates (water-insoluble fraction, WIF, and water-soluble and crystallizable fraction, WSCF) under the same reaction conditions. For the synthesis of PET-based alkyd resins, the depolymerization intermediates were used partially or completely instead of dibasic acid and/or diol components in alkyd resin formulations. In order to determine the optimum modification ratio for urethane-modified alkyd resin synthesis, the reference alkyd resin was reacted with toluene diisocyanate (TDI) at different molar ratios (NCO/OH: 1/1, 1/2, and 1/3), and the optimum NCO/OH ratio was determined as 1/1, according to the surface coating properties. And, then, all PET-based urethane-modified alkyd resins were prepared by the modification reactions of the PET-based alkyd resins with TDI at an optimum ratio. At the end of the study, it was observed that the use of waste PET intermediates (WIF or WSCF) did not cause any negative effects on physical/chemical surface coating and thermal properties; on the contrary, some properties were obtained as superior than that of the reference resin. In conclusion, it seems possible to use PET-based urethane-modified alkyd resin could be used as a cheap, environmentally friendly, and relatively economic binder component in synthetic paint formulations. In the synthesis of urethane-modified alkyd resin, using a certain amount of waste PET intermediate instead of dibasic acid and/or diol component will reduce raw material costs and also benefit the environment by re-evaluation of recycled PET. Thus, it could be both possible to recycle of post-consumer PET bottles, which are a valuable waste, and to provide cheap raw materials without compromising its features for paint formulations. These results are remarkable in terms of sustainability and waste management besides are also important for the economy and paint industry. [ABSTRACT FROM AUTHOR]