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Difunctional glycidyl azide polymer (GAP) is an energetic binder promising for propellant formulations. The multifunctional fluorine‐containing GAP has been synthesized to enhance its mechanical properties. This work outlined multifunctional GAP partially grafted with 1,2,3‐triazole‐5‐(α‐hydroxyl)‐fluorinated polyether (GAP‐g‐3F) synthesized by thermal and catalyst‐free azide‐alkyne cycloaddition reaction, in which the azide groups were from GAP and electron‐deficient alkynes from β‐propargyl‐α‐hydroxyl poly (tri‐fluoropropane glycidyl ether) (PHP3F). PHP3F was synthesized via the typical cationic ring‐opening polymerization of 2‐((2,2,2‐trifluoroethoxy) methyl) oxirane and propargyl alcohol as the initiator. The chemical structures, molecular weight, and thermal properties were characterized by FTIR, NMR, GPC, DSC, and TGA, respectively. HNMR results showed that 8 % of total azide groups in GAP were grafted. GAP‐g‐3F had a slightly higher glass transition temperature than that of GAP. The results of TGA showed that GAP‐g‐3F had suitable thermal decomposition resistance up to 200 °C. The thermal properties, mechanical properties, cross‐linking network structures, and microstructures of the polyurethane networks cured with hexamethylene diisocyanate trimer as a crosslinking agent were determined and compared by TGA, universal tensile test, swelling measurement, and SEM, respectively. The initial decomposition temperature of GAP‐g‐3F‐based polyurethane networks (GAP‐g‐3F‐PU) was around 220 °C, thus meeting the requirements for propellants. In addition, GAP‐g‐3F‐PU exhibited superior mechanical properties, showing an almost twelvefold increase in tensile strength to 16.9 MPa compared with difunctional GAP‐PU with 1.4 MPa tensile strength. The results of the swelling measurement revealed that the GAP‐g‐3F‐PU sample showed a higher crosslinking density in comparison to the GAP‐PU sample. SEM results indicated that the multifunctional fluorine‐containing GAP could enhance compatibility between the soft and hard segments of polyurethanes, leading to a decrease in their separation degree. This finding showed that the synthesis of a multifunctional GAP partially grafted with fluorinated polyether via a triazole ring may be a promising solution to decrease the separation degree increase of PUs, thereby improving the mechanical properties. [ABSTRACT FROM AUTHOR]

This work reports the kinetics of anionic ring‐opening polymerization of hexaethylcyclotrisiloxane (D3Et) with potassium trimethylsilanolate as initiator and diglyme and N,N‐dimethylformamide (DMF) as promoters. The polymerization rate of D3Et is influenced by the nature of promoters and the reaction temperatures. With the use of DMF as a promoter, the polymerization activation energy is 107.89 kJ/mol, and the polymerization rate constant at 110°C is 0.08466 min−1 with [P]/[I] = 3.0. Gel permeation chromatography and 29Si NMR spectra showed that the intermolecular redistribution occurred during the late stage of polymerization, which facilitated the synthesis of high‐molecular‐weight polydiethylsiloxane (PDES). Differential scanning calorimetry analysis showed that PDES exhibited a glass transition temperature of −142°C and complex crystallization phenomena. Thermogravimetric analysis illustrated that the PDES that was prepared using this method had good thermal stability with onset decomposition temperatures of 483 and 452°C under nitrogen and air conditions, respectively. This work presents innovative approaches for achieving a more energy‐efficient synthesis of PDES to meet the demands of industrial‐scale production. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

Photocurable polymer provides fast curable properties via ultraviolet (UV) light for 3D‐printed propellants. This work outlines the preparation and characterization of photocurable fluorinated polyether‐based reactive inks. Acrylate‐terminated poly‐2‐((2,2,3,3,3‐pentafluoropropoxy)‐methyl) ethylene oxide (P5F‐AA) was synthesized as photocurable binder through the esterification of acrylic acid, and the terminal hydroxyl group of poly‐2‐((2,2,3,3,3‐pentafluoropropoxy)‐methyl) ethylene oxide (P5F), which was synthesized through cationic ring‐opening polymerization of 2‐((2,2,3,3,3‐pentafluoropropoxy)methyl) oxy‐ethane (PFEE) by using butane diol as initiator. In comparison with P5F, P5F‐AA had a lower glass transition temperature (Tg) of −63.3°C. A new type of photocurable resin, which may be used for additive manufacturing of energetic materials, was prepared via UV radiation in an LED UV curing tank by using P5F‐AA as prepolymer, diphenyl (2,4,6‐trimethyl benzoyl) phosphine oxide (TPO) as photo‐initiator, and tri‐fluoroethyl acrylate (3F‐AA) and 1,6‐hexanediol diacrylate (HDDA) as mono‐ and multifunctional diluents, respectively. When the mass ratio of P5F‐AA/3F‐AA/HDDA binder matrix was 1:1:0.5, the sample exhibited maximal mechanical strength of 6.56 MPa with elongation at break of 13.38%, which was due to the introduction of HDDA effectively increasing the "entanglement" between molecular chains. Thermogravimetric analysis (TGA‐DTG) was utilized to evaluate the ability to decompose thermally of the binder matrix, and the results showed the initial degradation temperature started at nearly 181°C and two consecutive stages in thermal decomposition. Overall, the obtained results from the different techniques suggested that P5F‐AA/3F‐AA/HDDA binder matrix may be a photocurable reactive ink for 3D‐printed propellants, which would provide a certain reference value and guiding importance for design of reactive inks. [ABSTRACT FROM AUTHOR]

This contribution reports the efficient conversion of γ‐valerolactone and its derivatives, abundant but unexplored renewable feedstocks, into sustainable and degradable polythioesters via the establishment of the first isomerization‐driven ring‐opening polymerizations (IROPs) of corresponding thionolactone intermediates. The key to this success relies on the development of a new simple and robust [Et3O]+[B(C6F5)4]− cationic initiator which possesses high activity, exclusive selectivity, living nature, and broad scope of thionolactones. A complete inversion of configuration during IROP of enantiopure γ‐thionovalerolactone is also disclosed, affording isotactic semicrystalline polythioesters (Tm=87.0 °C) with mechanical property compared well to the representative commodity polyolefins. The formation of a highly crystalline supramolecular stereocomplex with enhanced thermal property (Tm=117.6 °C) has also been revealed. [ABSTRACT FROM AUTHOR]

• Synthesis of biobased polyamide 4 by anionic polymerization of 2-pyrrolidone. • Preparation of nanofibers by electrospinning and their characterization. • Test of degradation of nanofibers in water environment for a long period. • Nanofiber layers are hydrolytically stable. Based on renewable raw materials, polyamide 4 has excellent mechanical properties, high hydrophilicity, and cotton-like water sorption. The problem is its low thermal stability near its melting point, which does not allow melt processing. With the development of the technology of electrostatic spinning of polymers from solutions, the attention of researchers has returned to polyamide 4. In this work, nanofiber layers of polyamide 4 with molar masses of 18,000 and 280,000 g/mol and diameters of 350 ± 60 and 270 ± 10 nm, respectively, were prepared by electrostatic spinning from a mixed solution of formic acid and dichloromethane. Subsequently, the layers were subjected to degradation in phosphate buffer at 37 and 60 °C. The electrostatic spinning process was shown to result in a decrease in the molar mass of the samples. During degradation in buffer at pH 7.4, the molar mass does not change significantly, but there is a change in the structure of the nanofibrous layers by bonding of the fibers, especially for low molecular weight PA4. In contrast to other studies, polyamide 4 is hydrolytically stable even in the form of nanofiber layers. [ABSTRACT FROM AUTHOR]

Low dielectric photoinduced patterned materials have attracted extensive attention owing to their potential applications in integrated circuits and semiconductor devices. In this work, we synthesized a low dielectric polymer that can be used for photolithography. The monomer, 1-(4-vinylphenyl)-2-(4-benzocyclobutenyl)ethene (DVB-S-BCB), was synthesized from divinylbenzene (DVB) and 4-bromobenzocyclobutene (4-BrBCB) using the Heck reaction. Subsequently, P-DVB based on DVB-S-BCB was prepared by anionic polymerization. As the structure comprised thermally curable benzocyclobutene (BCB) groups and photocurable vinyl groups (UV/Thermal dual curing structure), P-DVB has been used for high-performance negative photosensitive resin with 2,6-bis(4-azidobenzylidene) cyclohexanone (BAC) as a photoinitiator. Photolithography was carried out using a 365-nm UV light source to obtain various patterns, and the research results indicate that photosensitive resins exhibit stable patterning processes at different curing stages. Besides, the cured P-DVB exhibited high thermal stability (T 5% above 420 °C in N 2), low dielectric constant (2.55 at 10 MHz), low dielectric loss (1.56 × 10−3 at 10 MHz), and excellent mechanical performance. These properties make P-DVB a potential photoresist that can be widely used as interconnected dielectrics. P-DVB containing vinyl groups and benzocyclobutene groups was synthesized by anionic polymerization. This resin exhibits low D k and high-resolution photo-imageable dielectric performance. Therefore, it is expected to be used for integrated circuits and semiconductor devices. [Display omitted] • Rapid synthesis of photosensitive resins with photo-thermal curing structures on a large scale, and at low cost. • Have high-resolution photo-imageable and process flexibility (spin coating or dry film, patterning, developing). • UV/Thermal double cured structure gives excellent mechanical properties, low dielectric properties and low CTE. • Widely used in high-density, low-power packages such as WLP, RDL, TSV, etc., promoting integration and miniaturization. [ABSTRACT FROM AUTHOR]

Copolymerization of diallylamine (DAA) and itaconic acid (IA) was synthesized using benzoyl peroxide as a free radical initiator, in dioxane as the solvent. The composition of the copolymer was determined by the nitrogen content using Edx. The solubility of the copolymer was also investigated. The water solubility of the synthesized copolymer depends on the comonomers' ratio. The structure of the copolymer was confirmed by 13C-NMR spectroscopy. To increase the water insolubility of the copolymers, and keep their hydrophilicity, the copolymer was allowed to react with chitosan to form a superabsorbent polymeric material (SP). The structure of the synthesized superabsorbent was confirmed using 13C-NMR spectroscopy. The thermal property of the (SP) was also investigated by TGA. The investigation of the chitosan-based superabsorbent, as water-retaining agents, was studied. The results revealed that the superabsorbent polymers exhibited a good swelling ability and salt tolerance. [ABSTRACT FROM AUTHOR]

Copyright of Silicone Material is the property of Silicone Material 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 weakly entangled ultrahigh molecular weight polyethylene (UHMWPE) was synthesized by a Ziegler‐Natta catalyst, where the titanium tetrachloride was anchored on the polystyrene (PS)‐modified silica. The PS chains were successfully incorporated into silica hierarchical pores even with the size less than 10 nm through the in situ free‐radical polymerization of styrene. The self‐diffusion coefficient and crystallization of probing molecules inside the pores were investigated by the pulsed field gradient NMR and thermoporosimetry to address the swollen behavior of incorporated PS blocks. This PS blocks compartmentalized the polyethylene chains, where the less entangled UHMWPE was synthesized with an exceptional activity at 70°C. The ubiquitous PS isolators effectively hindered the formation of chains overlaps during the polymerization, showing a long‐term efficiency to reduce the entanglements of nascent UHMWPE even at 4 h of polymerization The toughness/stiffness/strength balance of weakly entangled UHMWPE was significantly improved. [ABSTRACT FROM AUTHOR]

Neat and hybrid polyamide 12 (PA12) based powders are important raw materials for additive manufacturing. This study describes a facile method for the synthesis of pure, hybrid and copolymeric microparticulate materials based on one‐pot activated anionic ring‐opening polymerization (AAROP) of laurolactam in solution. The results reveal the possibility to obtain in good yields, for reaction times of 2 h and temperatures of up to 110°C neat and hybrid PA12 microparticles (MP) carrying metal or carbon fillers. Copolymeric PA12/PA6 MP can also be successfully prepared. All MP materials are analyzed by spectral, microscopy, thermal, and synchrotron X‐ray scattering methods in order to clarify their morphology, chemical and crystalline structure, melting and degradation behavior. The melting temperature of the PA12 MP is lower than of the commercial PA12, the presence of metal particles or copolymerization with PA6 additionally decrease it well below 170°C. The composites prepared by compression molding of PA12 MP display elastic modulus of up to 1.49 GPa, the stresses at yield and break reaching 50 and 69 MPa, respectively. It is concluded that the neat, hybrid, and copolymeric pulverulent materials obtained via microencapsulation by AAROP in solution may be useful in additive manufacturing processing. [ABSTRACT FROM AUTHOR]

UV‐initiated cationic frontal polymerization is exploited as a solvent‐free, extremely fast, and low‐temperature technique to obtain epoxy‐based adhesives. Epoxy formulations are prepared by blending commercial resins at different weight ratios and adding photo and thermal initiators at different percentages. In addition, the influence of other critical parameters, including the joint thickness, the nature of the adherends, and the temperature, is studied. As the reaction front is thermally sustained, the boundary conditions play a key role during the curing process and heat dissipation through the adherends in particular. The thermal properties of the epoxy formulation are studied through differential scanning calorimetry analysis, and the joint strengths are investigated by carrying out single lap off‐set shear tests under compression. The results demonstrate the feasibility of obtaining joints by means of the radical induced cationic frontal polymerization of the epoxy adhesives, which exhibit comparable epoxy group conversion and mechanical performances to the ones cured by traditional energy‐intensive techniques. [ABSTRACT FROM AUTHOR]

Preparing an epoxy resin with biomass resources as an alternative for bisphenol A is significant for sustainable and renewable development under great pressure of limited fossil resources and urgent environmental issues. Herein, we synthesized an epoxy oligomer P-DBP-EP-n derived from biomass magnolol through an efficient one-step glycidylation. P-DBP-EP-n exhibited a low viscosity of 11.7 Pa·s at room temperature, endowing it with excellent processability as diglycidyl ether of bisphenol A (DGEBA) and magnolol-based epoxy monomer EDBP. Then P-DBP-EP-n was cured with a diamine curing agent, 4,4'-diaminodiphenyl methane (DDM), and following thermal addition polymerization of allyl units. Compared with DGEBA/DDM and EDBP/DDM, P-DBP-EP-n/DDM possessed a higher glass transition temperature (Tg) (304 to 167 and 226 °C), implying distinguished heat resistance. Furthermore, the tensile properties and notched impacted strength of P-DBP-EP-n/DDM were better than EDBP/DDM (20.7 to 19.4 MPa, 2.0 to 1.6 GPa, and 2.5 to 2.0 kJ/m²). The initial degradation temperature and char residue of P-DBP-EP-n/DDM were 421 °C and 35.2%, with a 13.5 and 101% increase compared with those of DGEBA/DDM, respectively. Additionally, P-DBP-EP-n/DDM displayed outstanding flame retardancy with V-0 rate for the vertical burning test and limiting oxygen index value of 47.7%, which was almost twice as much as that of DGEBA/DDM. This study offers a promising and feasible pathway to obtain a fully bio-based epoxy resin substituted for petroleum-based DGEBA with distinguished processability, heat resistance, and flame retardancy. Comprehensive properties of the bio-based thermosets are expected to be further regulated by the thermal addition polymerization of allyl units. [ABSTRACT FROM AUTHOR]

In the available research, firstly a new 3-acetamido phenyl acrylate (APhA) monomer and a novel copolymer containing acetamido phenyl group were synthesized. 3-acetamido phenyl acrylate (APhA) monomer was acquired by the reaction of acryloyl chloride and N-(3-hydroxyphenyl) acetamide. 3-acetamido propyl methacrylate (AAPMA) monomer was prepared in our previous study. A series of copolymers were prepared using these monomers in different mole ratios by free-radical polymerization method at 70 °C The structure of P(AAPMA-co-APhA) copolymer systems was characterized by FT-IR and NMR techniques. Thermal characteristics of P(AAPMA-co-APhA) copolymers were evaluated through thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) in an N2 atmosphere. Due to the presence of the amide group, we can say that the polymer with the least weight loss and the highest residue percentage at 500 °C is poly(APhA). AC electrical conductivity and dielectric and electrical parameters were analyzed in a range of 100 Hz–20 kHz frequency. The dielectric constant values of poly(AAPMA-co-APhA0.63) and P(AAPMA-co-APhA0.30) were 4.98 and 4.57 respectively. According to the results, the dielectric value decreased as the APhA units increased. [ABSTRACT FROM AUTHOR]

Two different Schiff bases, viz. 1-{4-[(5-bromo-2-hydroxybenzyliden)amino]phenyl}ethanone (5-Br-2HBAPE) and 1-{4-[(4-hydroxybenzylidene)amino]phenyl}ethanone (4-HBAPE), have been prepared by condensation of 5-bromosalicylaldehyde and 4-hydroxybenzaldehyde with 4-aminoacetophenone in ethanol at molar ratio of 1:1. Then, Schiff base methacrylate monomers, i.e., 2-(((4-acetylphenyl)imino)methyl)-4-bromophenylmethacrylate (APIMBPM) and 2-(((4-acetylphenyl)imino)methyl)phenylmethacrylate (APIMPM), were synthesized by reaction of each Schiff base compound with methacryloylchloride at 0°C to 5°C. Schiff base methacrylate polymers poly(APIMBPM) and poly(APIMPM) were then prepared by free-radical polymerization in tetrahydrofuran (THF) at 70°C using azobisisobutyronitrile (AIBN) as initiator. The structure of 5-Br-2HBAPE, 4-HBAPE, APIMBPM, APIMPM, poly(APIMBPM), and poly(APIMPM) was confirmed by Fourier-transform infrared (FT-IR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The thermal behavior of poly(APIMBPM) and poly(APIMPM) was studied by differential scanning calorimetry (DSC) and thermogravimetry (TG). The glass-transition temperature (Tg) of poly(APIMBPM) and poly(APIMPM) was found to be 113°C and 108°C, respectively. The residual amount of poly(APIMBPM) and poly(APIMPM) at 1000°C was found to be 45.60% and 26.35%, respectively. Dielectric and conductivity measurements were carried out on the Schiff base methacrylate polymers by impedance analysis as a function of frequency. The conductivity of poly(APIMBPM) and poly(APIMPM) was found to be 1.30 × 10−9 S cm−1 and 2.14 × 10−9 S cm−1, respectively. Scanning electron microscopy (SEM) was used to investigate the morphology of the Schiff base methacrylate polymers, and their antimicrobial activity against bacteria and fungus was determined by disk diffusion method. Poly(APIMBPM) exhibited good antibacterial property against Klebsiella pneumonia. Poly(APIMBPM) and poly(APIMPM) exhibited good antifungal action against Candida albicans. We thus describe the synthesis of different Schiff base methacrylate polymers and their thermal behavior, electrical properties, and antimicrobial activities. [ABSTRACT FROM AUTHOR]

[Display omitted] An efficient synthesis of the new star-shaped polymer with azido-containing oligomer rays is based on construsion of these rays on the β-cyclodextrin nitrate core employing 3,3-bis(azidomethyl)oxetane as the key reactant. The formation of star-shaped structure was proved. Thermal and optical properties of the synthesized polymers were assessed. [ABSTRACT FROM AUTHOR]

• Effect of replacing MgO by Nb 2 O 5 in the parent Na-Ca-P-Al-O glass system is studied. • Al suppresses Nb and accelerates Mg release process from the glasses into PBS. • Al and Mg addition decreases while Nb increases the polymerization of glass network. • Al and Nb contents control the glass transition temperature. • Glass thermal stability is highly correlated only with the Nb content. In vitro dissolution, structure, and thermal properties of the glass series Na 2 O-MgO CaO Nb 2 O 5 -Al 2 O 3 -P 2 O 5 were studied. The dissolution behavior in phosphate-buffered saline (PBS) confirmed the potential bioactive properties of tested glasses. The dissolution process was found to depend on the Al, Nb, and Mg contents. Al, respectively, suppresses the Nb and accelerates the Mg release process from the glasses. Moreover, Al stays highly bonded in the phosphate network during 14 days of immersion. In all glasses, the phosphate network was found to be highly disrupted and built mostly of Q1 units. Al and Mg addition decreases the polymerization of the glass network. The Nb addition effect was found to be the opposite. Thermal properties were correlated mostly with the Nb and Al contents. However, the fragility index of glasses increases with the content of P and Al. [ABSTRACT FROM AUTHOR]

Novel hybrid materials of the PB-b-P(o-Bn-L-Tyr) and PI-b-P(o-Bn-L-Tyr) type (where PB: 1,4/1,2-poly(butadiene), PI: 3,4/1,2/1,4-poly(isoprene) and P(o-Bn-L-Tyr): poly(ortho-benzyl-L-tyrosine)) were synthesized through anionic and ring-opening polymerization under high-vacuum techniques. All final materials were molecularly characterized through infrared spectroscopy (IR) and proton and carbon nuclear magnetic resonance (1H-NMR, 13C-NMR) in order to confirm the successful synthesis and the polydiene microstructure content. The stereochemical behavior of secondary structures (α-helices and β-sheets) of the polypeptide segments combined with the different polydiene microstructures was also studied. The influence of the α-helices and β-sheets, as well as the polydiene chain conformations on the thermal properties (glass transition temperatures, thermal stability, α- and β-relaxation) of the present biobased hybrid copolymers, was investigated through differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dielectric spectroscopy (DS). The obtained morphologies in thin films for all the synthesized materials via atomic force microscopy (AFM) indicated the formation of polypeptide fibrils in the polydiene matrix. [ABSTRACT FROM AUTHOR]