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BACKGROUND RESULTS CONCLUSION Pea protein isolate (PPI) is gaining increasing popularity in the food industry. It provides a diverse range of health benefits, such as hypoallergenic and gluten‐free characteristics. However, the functional performance of PPI is hindered by its low solubility and poor stability. Therefore, in this article, PPI and dextran (DX) of different molecular weights were grafted to investigate the effects of grafting DX with different molecular weights on the interface properties and antioxidant properties of PPI. Additionally, the stability and digestive properties of the glycated PPI nanoemulsion system were explored.The result showed that the grafting degree of PPI–DX conjugates (PPI–DC) decreased with an increase in the molecular weight of DX. Surface hydrophobicity, antioxidant activity and solubility of PPI–DC were significantly improved after grafting compared with PPI and PPI–DX mixtures (PPI–DM). Astaxanthin‐loaded emulsions stabilized by grafted conjugates had smaller droplets and higher astaxanthin encapsulation rate compared to PPI emulsions. In vitro digestion demonstrated that the bioavailability of PPI–DC emulsions was higher than of PPI emulsion. Furthermore, after 24 days of storage, retention rate of astaxanthin‐loaded emulsions prepared by conjugates remained above 70%, surpassing that of PPI emulsion.These results indicated that DX grafting can improve the emulsion properties of PPI. In addition, the DX with a molecular weight of 5 kDa showed the most significant improvement. This study contributes to the advancement of natural emulsifiers by modifying PPI through glycation, and furnishes a valuable reference for its utilization in functional foods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Cross‐linked polyethylene (XLPE) insulation has been used in most advanced power cable technology. Strategies for decreasing the amount of antioxidants have been proposed to reduce conductivity further. In this study, the structural design of a new dual‐functional antioxidant has been established. Theoretical investigation of the antioxidative behavior and grafting reaction of the new antioxidant by ultraviolet (UV) radiation was performed using the density functional theory (DFT) method. The reaction potential energy information of the six reaction channels at the B3LYP/6‐311+G (d,p) level was obtained. Frontier molecular orbitals (MOs) and natural bond orbital (NBO) charge populations of the designed antioxidant molecule were analyzed. The calculation results indicate that the reaction Gibbs energy barrier of the designed antioxidant and O2 required to achieve the antioxidative effect is about 0.8 eV lower than that of the polyethylene chain. Moreover, due to the lower reaction Gibbs energy barrier, the reaction active site of the designed antioxidant accepting H is located on the O of the CO groups. The proposed mechanism would be beneficial to understanding the molecular functions of antioxidants and further broadening the design ideas of thermoplastic insulation materials for future advanced power cables. [ABSTRACT FROM AUTHOR]

Starch grafted polymers have attracted widespread attention due to their high viscosity, temperature resistance, salt resistance, and biodegradability・ However, the performance of the products is greatly affected by synthesis conditions, and the study of the principle and influencing factors of starch graft polymerization reaction has guiding significance for the application of the products・ The synthesis method and reaction mechanism of starch graft polymers were introduced, and the effects of monomer ratio of starch and vinyl monomer, reaction temperature, initiation method, pH value, starch gelatinization time, and reaction time on free radical polymerization were discussed・ The performance of the product can be significantly improved by optimizing synthesis conditions・ This article summarizes the research and application progress of starch grafted polymers by domestic and foreign scholars in the fields of fluid loss additive, flocculants, adhesives, water-absorbing materials, adsorbents, corrosion inhibitors, etc. And new suggestions were put forward for the grafting synthesis method, and the future development trends of starch grafted polymers were discussed. [ABSTRACT FROM AUTHOR]

In this study, the UiO-66-NH2@PMAA metal-organic framework was prepared by using a hydrothermal reaction coupled with the gamma-ray irradiation method. The chemical structure of the product was studied using FTIR and XPS before and after irradiation, indicating the efficient development of the grafting reaction. The DSC results revealed a drop in the melting point of UiO-66-NH2@PMAA material, which might be attributed to PMAM grafting. Following that, different MOF materials were suction-filtered onto the surface of the membrane, and the alteration of their contact angle with time was recorded, indicating the enhancement of UiO-66-NH2@PMAA materials' hydrophilicity. The modified MOF material has better dispersibility in aqueous solutions, providing reference significance for its application in related fields. [ABSTRACT FROM AUTHOR]

Poly(S-bioallethrin) (PSBA) was grafted onto the polyvinylidene fluoride (PVDF) molecular chain through a gamma-ray irradiation method to prepare the PVDF-g-PSBA membrane. Fourier transform infrared spectroscopy (FTIR) of different membranes confirmed the effective progress of the grafting reaction. The microstructure of the membrane before and after irradiation was analyzed by scanning electron microscope (SEM), illustrating that gamma-ray irradiation did not cause damage to the membrane structure. The original PVDF membrane and the modified PVDF-g-PSBA membrane were immersed in an Escherichia coli culture medium, and the antibacterial effects of membranes were tested, confirming the positive effect of the PVDF-g-PSBA membrane on inhibiting bacterial growth. This research could have market application value in terms of altering membrane materials and enhancing membrane performance. [ABSTRACT FROM AUTHOR]

Ordinary polypropylene homopolymer (PP) has low melt strength and mechanical properties, which greatly restricts its application in foam molding. In this work, high melt strength polypropylene (HMSPP) is successfully fabricated by melting grafting technique using dicumyl peroxide as an initiator and trimethylolpropane triacrylate (TMPTA) as a grafting monomer. The effects of different reaction temperatures and formulas on modified PP are investigated. The results show that the introduction of TMPTA will reduce the melt flow rate, and improve the grafting ratio, torque, melt strength (MS), mechanical properties, thermal stability, and crystallization rate of polypropylene. It is found that HMSPP prepared at 170 °C 1.2 Phr TMPTA has the best comprehensive properties, with MS increased by 3.8 times, elongation at break increased by 120%, flexural modulus increased by 25%, impact strength increased by 33.3%, and thermal decomposition temperature increased by 52.6 °C. In addition, PP/HMSPP is extruded and foamed, and the results show that the foaming performance of HMSPP is better than that of PP. In general, the introduction of TMPTA improves the mechanical properties, melt strength, foaming property, and thermal stability of PP. [ABSTRACT FROM AUTHOR]

High‐performance polypropylene (PP) foam is a vital polymer product in industrial areas. However, the poor melt strength of ordinary PP homopolymer limits its foaming molding. In this work, high melt strength polypropylene (HMSPP) is prepared by using styrene (St) and tripropylene glycol diacrylate (TPGDA) as comonomers, and then PP foams are prepared by mold foaming method. The results show that adding St in the grafting process of TPGDA will obviously improve the melt strength of the PP matrix, and its melt strength (28 184 Pa.s) is 7.4 times higher than that of pure PP. HMSPP foam has more regular and uniform cells and higher cell density, which significantly improves the sound and thermal insulation properties of PP foam. Compared with pure PP foam, the average sound transmission loss (52.9 dB) of HMSPP foam with a low foaming ratio increased by 64%, and the thermal conductivity (0.0867 W mK−1) decreased by 46%. Therefore, the obtained HMSPP foam can be used in sound insulation or thermal insulation area. This work provides an available route for the high‐performance utilization of PP foam. [ABSTRACT FROM AUTHOR]

Silylation is an effective means of cellulose modification. However, the condensation reaction process between the hydrolysis products of the silane coupling agent and cellulose, as well as the structure of the coating, which both have a strong influence on the wettability, are still controversial. In this paper, the reactions of different methyltriethoxysilane hydrolysis products with cellulose were simulated via the density functional theory method. The reaction activity centers of the different methyltriethoxysilane hydrolysis products in an ethanol solution were analyzed via the front-line orbital theory and the Fukui function. The silylation reaction of different methyltriethoxysilane hydrolysis products in an ethanol solution on the cellulose surface were investigated via the transition state theory. The results show that although the initial hydrolysis product has the lowest grafting energy barrier, considering the whole process of grafting and condensation on the cellulose surface, the hydrolysis product with two hydroxyl groups is more favorable for the growth of organosilicon on the cellulose surface, so it is desirable to control the reaction where this product is dominant. In addition, the silylation process on the cellulose surface is more inclined to a multilayer coating mechanism.

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.)

Summary: An innovative functional food with symbiotic and functional potential was produced by combining probiotic milk kefir, and white grape‐seed pomace obtained by UAE (ultrasound‐assisted extraction) rich in catechin and glycosylated flavonoids. The milk kefir was fortified by adding, after 24 h of fermentation, a polymer of inulin grafted with seed extract. The inulin/grape extract‐enriched polymer showed a higher antioxidant profile (P < 0.05). Simulated in vitro digestion demonstrated that 50 g of the kefir product would result in the delivery of antioxidants equivalent to 300 mg of ascorbic acid. The integrity of the intestinal barrier functions was not compromised by kefir treatments (at 10 μg mL‐1). [ABSTRACT FROM AUTHOR]

Chemical modification in surface of cellulose nanofibrils CNFs (20 nm) from an endemic and non-significant value-added, Argentine bamboo, was developed. The modification in the CNFs was carried out with three simple routes using a low molecular weight polylactic acid synthesized in our laboratory (PLA1). The first step comprises of protection of the hydroxyl groups of PLA1 through a benzoylation (PLA1Bz). The next step consisted of the activation of carboxyl groups using thionyl chloride and the last reaction was the grafting of the modified PLA onto the CNFs (PLA1Bz-g-CNF). The covalently functionalization is confirmed by spectroscopically techniques as well as PLA1Bz-g-CNFs were characterized by thermal analyses. The PLA1Bz-g-CNFs were taken up such as nanocharges to improve properties of compatibilization and changing surface properties in films based on PLA. The comparison between the films with PLA1Bz-g-CNFs with respect to the physic mixture of the components (PLA1Bz/CNF), shows an improvement in the thermal, mechanical, and surface properties of the material, particularly when 5% of PLA1Bz-g-CNFs was added. The dispersive (γS D) component of film is increased in 36.1 mN/m respect to 29.3 mN/m from the films obtained with the physic mixture nanofibrils without modification and a plasticizing effect was noticed in the final material. • Chemical grafting with short PLA on CNF was used to obtain better compatibility between the hydrophobic PLA matrix and CNFs. • Nanofibrils modified showed an improved thermal stability than unmodified nanofibrils. • Modified CNFs added into the PLA matrix films, reduced the polar contributions of the nanofibrils in the films. • Low molecular weight PLA chains grafted onto the nanofiber surface inhibit the nucleating effect, thus crystallinity in films. • Plasticizing effect in PLA films with the addition of modified nanofibers was noticed in the mechanical properties. [ABSTRACT FROM AUTHOR]

The present study reports the synthesis of poly(vinyl alcohol)-g-acrylamide (PVA-g-AAm) copolymer by grafting in presence of benzoyl peroxide initiator via free radical polymerization. The crosslinking was done in-situ by the addition of glutaraldehyde. The membranes were prepared by solution casting and solvent evaporation technique. The different amounts of heteropolyacid i.e Phosphotungstic acid hydrate (H3PW12O40) (HPA) was incorporated into the PVA-g-AAm membranes. The membranes were sulfonated by soaking in the solvent bath. The prepared membranes were characterized by FTIR to confirm the formation of the copolymer. The surface morphology is studied using SEM. The water uptake test, contact angle measurement, and ion exchange capacity were conducted to measure the physical properties of the prepared hybrid membranes. The modified membranes showed good proton conductivity at 50 °C around 10−2 Scm−1 and lower H2 permeability as compared to standard Nafion 115 membrane. The membrane containing 10 wt. % HPA PVA-g-AAm sulfonated membranes performed better with 0.578 Scm−1 as compared to plain PVA-g-AAm sulfonated membrane which shows the conductivity 0.248 Scm−1 under fuel cell atmosphere. The obtained results suggested that the incorporation of HPA into the proton-conducting copolymers is a good candidate for elevated temperature operation of proton exchange membrane fuel cells. Application to operate fuel cells at elevated temperatures is now being investigated.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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.)

1,2,3,4-butanetetracarboxylic acid (BTCA) has been explored as formaldehyde-free crosslinking agent for many years. In this study, a novel kinetic model for cellulose reacted by BTCA was proposed and the factors that influenced the model parameters were investigated in detail, which could help us understand crosslinking mechanism clearly. Kinetic model, which is a consecutive reaction model, consisting of grafting (esterifying) reaction rate constant and crosslinking reaction rate constant, was deduced. The rate of the whole reaction depends on the rate of grafting reaction, which is related to the diffusion of free BTCA in pores of cellulose. However, the rate of crosslinking reaction depends on thermal vibration of cellulose chain grafted by BTCA, which is more sensitive to the change of curing temperature, especially when the temperature is higher than 150 °C. The Arrhenius activation energies of grafting and crosslinking reactions are 86.3 kJ/mol and 102.8 kJ/mol, respectively, showing high temperature is more conducive to increase the rate of crosslinking reactions comparing with grafting reaction. Moreover, the whole reaction is also affected by catalyst of SHP, which could react with BTCA anhydride to form BTCA-SHP compounds. Due to lower electron cloud density of carbonyl groups, BTCA-SHP compounds have much higher reactivity compared with BTCA anhydrides, which are beneficial to be attacked by hydroxyl groups in cellulose to form ester bonds, imparting excellent wrinkle-resistance to cotton fabrics. [ABSTRACT FROM AUTHOR]

In this study, we report the synthesis and characterization of novel nanocomposite namely doubly functionalized chloromethyl-calix[4]arene-methoxy grafted silylated clay (SC-C[4]). The silylation of nanoclay (thickness of the sheets ≈ 1 nm) was performed using (3-aminopropyl)trimethoxysilane (APTMS) (height ≈ 4.55 Å) coupling agent. The resulting organoclay was characterized by various techniques such as X-ray diffraction (XRD), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), and 29Si and 13C solid-state NMR. The XRD results suggested the presence of a double layer of silanes molecules into the clay galleries of nanoclay minerals by increasing in the basal spacing. While the IR, 29Si and 13C solid-state NMR, and TGA analysis demonstrated the successful silylation of clay by the appearance of novel absorption bands, the changes in the chemical environment and the peaks degradation in the range 200 to 500 ° C related to aminosilane molecules, respectively. The calix[4]arenes derivatives were synthesized and characterized by IR spectroscopy and 1HNMR. The results showed that calix[4]arene was functionalized at the lower and upper rim. The grafting of the doubly functionalized calix[4]arene onto clay surfaces was performed through nucleophilic reaction. Structure, thermal properties of the nanocomposite SC-C[4] were also investigated. All data approved the successful grafting of para-chloromethyl-calix[4]arene-OMe onto clay surfaces. [ABSTRACT FROM AUTHOR]

Due to the fact that natural cellulose cannot be melted, it is still challenging to process this biopolymer via thermoplastic processing methods. Herein, polycaprolactone diol was grafted onto regenerated cellulose (RC) via hydroxyl/isocyanate chemistry in dimethyl sulfoxide to endow cellulose with thermoplasticity. By adjusting the reaction parameters including the feeding ratios of reactants and reaction time, several homogeneous cellulose grafted polyurethanes (RC-g-PU) with the degree of substitution (DS) ranging from 0.49 to 1.48 and degree of polymerization ranging from 1.84 to 3.3 were synthesized. The thermoplasticity of the obtained RC-g-PU was well characterized by differential scanning calorimetry and optical microscope. The results revealed that the prepared RC-g-PU with DS values ranging from 1.01 to 1.48 can be melted at above 168.4 °C because PU side chains can serve as internal plasticizers and prevent the restacking of cellulose chains. Eventually, the synthesized thermoplastic RC-g-PU can be processed into transparent films by hot-pressing at 170 °C. Therefore, this research constructs a melt-processable cellulose derivative by a simple and engineering method. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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 the present work, an experimental procedure was developed in order to obtain different amounts of titanium oxide highly dispersed on the surface of mesoporous ordered silica material, SBA-15 type. The procedure is based on successive grafting reactions using small quantities of titanium alkoxide precursor that allow obtaining high amounts of highly dispersed titanium oxide, even after calcination at 500 °C, and at the same time, preserves the mesopore structure of the silica. The proposed procedure avoids the aggregation of titanium oxide that forms crystallites, which can be detected by XRD, and consequently closes the mesopores. This behavior produces the artifact known as Tensile Strength Effect (TSE) which is detected by textural analysis. Mesoporous silica containing highly dispersed titanium oxide was applied as modifier MWCNT paste electrode for evaluation of sulfamethoxazole (SMZ) and trimethoprim (TMP). The electrode presents excellent response for simultaneous determination of both antibiotics in a wide linear concentration range. It presents high sensitivity, 10.5 and 25.1 nA μmol−1·L and low detection limit 60 and 70 nmol L−1, for SMZ and TMP respectively. Image 1 • Reveling route to obtain titania highly dispersed inside of SBA-15 mesopores. • Identifying TSE effect in SBA-15 grafted with large amount of titania. • Simultaneous determination of SMZ and TMP antibiotics. [ABSTRACT FROM AUTHOR]

Abstract: To expand the application of nanofibrillated cellulose (NFC), the increase of its hydrophobicity is considered to be critical. In the present work, hydrophobic NFC powder was prepared through chemical modification with alkyl ketene dimer (AKD). The results showed that when modifying the original NFC with an AKD loading of 0.7 g/g (based on dry cellulose) at 110 °C for 6 h, the AKD graft yield of approximately 40% (based on initial cellulose mass) was successfully achieved. The Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that the grafting reaction mainly occurred on the fibre surface and the nanocrystal structure of cellulose was preserved after chemical modification. The thermogravimetric analysis results indicated the thermal stability increased with increasing the AKD graft yield. Scanning electron microscopy observations indicated that no significant differences in fibril morphology before and after AKD modification. Water contact angle measurements of the films produced from original and AKD-modified NFC powders demonstrated the significant increase in hydrophobicity of NFC after modification with AKD. Moreover, the hydrophobicity of AKD-modified NFC increased with increasing AKD graft yield.Graphical abstract: [ABSTRACT FROM AUTHOR]

The graft copolymer of locust bean gum (LBG) and acrylamide has been synthesized by microwave assisted method using potassium persulphate (KPS) as an initiator in aqueous medium. Different reaction parameters such as time, initiator concentration, monomer concentration, polymer concentration, and microwave power were studied to get maximum graft copolymer. The grafted copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The graft copolymer exhibited pH switching on-off behavior depending on the pH of the external medium. Flocculation capacity of LBG and LBG-graft-polyacrylamide for both coking and non-coking coals has been studied. Results indicated that the graft copolymer exhibited good flocculation properties compared to native polymer. The graft copolymer was non-toxic in the acute toxicity study, since the acute single dose did not cause any toxic signs, or symptoms. All mice treated with the graft copolymer survived beyond the 14 days of observation period.

Silks are of central importance as smart natural biomaterials and are attracting increasing attention for their biomimetic potential due to their sophisticated molecular structure, self‐assembly mechanism, impressive mechanical properties, biocompatibility, and biodegradability. The versatility of silk proteins (SP) allows the chemical modification of silk‐based materials with diverse morphologies under harsh conditions. The chemical modification of amino acids within SP enables the expanded generation of new biomaterials and the extension of their potential functional applications. The authors review the current chemical modification strategies and routes for the functionalization of SP. [ABSTRACT FROM AUTHOR]

Nano-titanium (Nano-Ti) was prepared by high-energy ball milling from pure Ti power and grinding agents (Epoxy resin) at room temperature. The effect of milling time on structure and properties of Nano-Ti polymer were investigated systematically. The results show that high-energy ball milling is an effective way to produce Nano-Ti polymer. The dispersion stability and compatibility between Ti power and grinding agents are improved by prolonging the milling time at a certain degree, that is to say, the optimization milling time is 240 min. The particle size of Ti powder and the diffraction peaks intensity of Ti decrease obviously as the milling time increases due to the compression stress, shear friction and other mechanical forces are formed during ball milling. FT-IR result displays that the wavenumber of all the bands move to lower wavenumber after ball milling, and the epoxy ring is open. The system internal energy rises owing to the broken epoxy group and much more Nano-Ti is formed to promote the grafting reaction between Nano-Ti and epoxy resin. The results from TEM and XPS also prove that. And the grafting ration is maximum as the milling time is 240 min, the mass loss ratio is 17.53%. [ABSTRACT FROM AUTHOR]

During the process of recirculating drilling fluids, the removal of useless solids, especially submicron particles, in drilling fluids is the most problematic issue in drilling operations. The cost and efficiency of currently used technologies are the two issues that have to be addressed urgently. In this study, the novel flocculant CMC- g -DMDAAC was synthesized by grafting diallyl dimethyl ammonium chloride (DMDAAC) onto carboxymethyl chitosan (CMC). The physicochemical structure of the CMC- g -DMDAAC product was characterized by Fourier-transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, and determination of the ζ-potential. A kaolinite suspension, a bentonite suspension, and drilling fluids from an oilfield were selected to evaluate the flocculation performance of CMC- g -DMDAAC by testing the products’ turbidities and particle size distributions. In comparison, the flocculation performances of chitosan, CMC, and commercial hydrolyzed polyacrylamide (HPAM) were also tested under the same conditions. The results showed that CMC- g -DMDAAC exhibited steady flocculation performances for all clay suspensions and drilling fluids at all pH ranges at low dosage. The scavenging capacity of submicron particles in drilling fluids was also excellent for the tested product. [ABSTRACT FROM AUTHOR]

This study uses a reactive extrusion for the grafting of maleic anhydride on polylactic acid in order to form polylactic acid grafted maleic anhydride that serves as a compatibilizer between polylactic acid and carbon fiber. The effects of different ratios of the free radical initiator to maleic anhydride as well as the amounts of polylactic acid grafted maleic anhydride on the mechanical properties, interfacial compatibility, thermal behaviors, and electrical properties of the polylactic acid/carbon fiber composites are discussed. The test results indicate that using polylactic acid grafted maleic anhydride as compatibilizer improves the interfacial compatibility of polylactic acid/carbon fiber composites, which in turn contributes to a high electrical conductivity and the electromagnetic interference shielding effectiveness, while decreasing the surface resistance and increases. In addition, the amount of polylactic acid grafted maleic anhydride has a positive influence on their tensile properties, flexural strength, and impact strength. The differential scanning calorimetry results indicate that a high polylactic acid grafted maleic anhydride content is also conducive to crystallinity, but is not in related to the melting temperature. According to the scanning electronic microscope observation, the fractured composites that are inflicted by an impact have considerably few traces of the fibers being pulled out, which is ascribed to polylactic acid that can completely enwrap carbon fiber. Therefore, the incorporation of polylactic acid grafted maleic anhydride is proven to strengthen polylactic acid/carbon fiber composites, exemplified by their improved interfacial compatibility and properties. [ABSTRACT FROM AUTHOR]

A polypyrrole-carboxylic acid derivative (PPy-COOH) was covalently anchored on the surface of hexamethylene diisocyanate (HDI)-modified graphene oxide (GO) following two different esterification approaches: activation of the carboxylic acids of the polymer by carbodiimide, and conversion of the carboxylic groups to acyl chloride. Microscopic observations revealed a decrease in HDI-GO layer thickness for the sample prepared via the first strategy, and the heterogeneous nature of the grafted samples. Infrared and Raman spectroscopies corroborated the grafting success, demonstrating the emergence of a peak associated with the ester group. The yield of the grafting reactions (31% and 42%) was roughly calculated from thermogravimetric analysis, and it was higher for the sample synthesized via formation of the acyl chloride-functionalized PPy. The grafted samples showed higher thermal stability (~30 and 40 °C in the second decomposition stage) and sheet resistance than PPy-COOH. They also exhibited superior stiffness and strength both at 25 and 100 °C, and the reinforcing efficiency was approximately maintained at high temperatures. Improved mechanical performance was attained for the sample with higher grafting yield. The developed method is a valuable approach to covalently attach conductive polymers onto graphenic nanomaterials for application in flexible electronics, fuel cells, solar cells, and supercapacitors.

In this study, the PPS/MWCNTs/AlN composite was prepared with poly(phenylene sulfide) (PPS), covalent functionalized multi-walled carbon nanotubes (fMWCNTs), and aluminum nitride (AlN) via melt-blending techniques. The AlN is a fascinating non-oxidizing ceramic material having the highest thermal conductivity among the ceramic materials. In order to introduce the functional groups on the surface of the AlN particles, a silane coupling agent was used as it is able to graft with the functional groups on the covalent functionalized MWCNTs. The silanization reaction of the AlN was confirmed qualitatively and quantitatively by FT-IR (Fourier Transform Infrared Spectroscopy), and XPS (X-ray Photoelectron Spectroscopy). The grafting reaction of the AlN particles on the MWCNTs was confirmed using UV-Vis (Ultraviolet-Visible Spectroscopy), FE-SEM (Field-Emission Scanning Electron Microscopy) and FE-TEM (Field-Emission Transmission Electron Microscopy) images. The grafting reaction was accomplished by observing the change of the transmittance, the morphology of the AlN particle bonded to the MWCNTs. For the morphological changes of the fractured surface of the PPS/MWCNTs/AlN composites by FE-SEM, the hybrid filler was homogeneously dispersed on the PPS matrix when the AlN particle was grafted on the MWCNTs. The homogeneous distribution of the hybrid filler acts as a heat transfer path, which led the higher thermal properties, such as thermal conductivity, thermal resistance, and melting temperature than those of not grafted MWCNTs. [ABSTRACT FROM AUTHOR]

Poly( D,L-lactide) (PLA) is a biodegradable polymer widely used in medical applications, whose properties can be diversified by the incorporation of multifunctional nanoparticles. In this report, the microwave-assisted ring-opening polymerization of D,L-lactide in the presence of ZnO nanoparticles was conducted to produce ZnO- graft-PLA nanocomposites. A comparative kinetic study of polymerization processes in mono-modal and multi-modal microwave reactors was addressed. Thanks to spectroscopic, thermal, and microscopic characterizations, the simultaneous formation of free PLA chains and grafted ones on ZnO nanoparticle surface was demonstrated, and the resulting products were carefully analyzed. [ABSTRACT FROM AUTHOR]

Embora a reticulação do polietileno efetuada através de processo de extrusão reativa, envolvendo a graftização de silanos vinílicos na cadeia polimérica, seja um processo bastante utilizado industrialmente, poucos estudos têm sido publicados sobre a influência das variáveis de processamento nas propriedades do polímero. Neste trabalho, foi avaliado o efeito das condições de processamento e do sistema reacional no índice de fluidez (MFI), no teor de gel e nas propriedades térmicas do polietileno linear de baixa densidade (LLDPE), graftizado com vinil-trimetóxi-silano (VTMS) na presença de baixas concentrações de peróxido de dicumila (DCP) e reticulado com água. Uma metodologia estatística demonstrou que o teor de silano é a variável de processamento mais significativa, quando a reação é efetuada utilizando 0,02% p/p de DCP. Aumento significativo do teor de gel do LLDPE foi obtido utilizando uma concentração maior de DCP (0,07% p/p). O processo de formação de ligações cruzadas causou aumento na estabilidade térmica e redução significativa no grau de cristalinidade, nas temperaturas de fusão e de cristalização e nas entalpias de fusão do LLDPE. Os espectros de infravermelho (FTIR) e o aumento da estabilidade térmica demonstram que houve formação de ligações cruzadas no polímero via pontes siloxano.Although silane-modified polyolefins have become an industrial process, little data have been published on the dependence of silane grafting reactions and the properties of crosslinked polyolefins on reaction parameters. Here we studied the melt grafting of vinyl trimetoxi silane (VTMS) onto linear low density polyethylene (LLDPE) promoted by dicumyl peroxide (DCP) in a single screw extruder followed by crosslinking reaction in hot water. The influence of grafting formulations and processing conditions on the melt flow index (MFI), gel content and thermal properties of grafted and crosslinked LLDPE was evaluated using a statistical design. The silane content was the most important variable when the reaction was performed with a low concentration of DCP (0.02 wt. (%)). Samples with significant gel content, however, were obtained with 0.07 wt. (%) of DCP. A decrease in the melt temperature and in the degree of crystallinity of LLDPE, as determined by differential scanning calorimetry (DSC) melting enthalpies, was observed as a result of crosslinking formation. The thermogravimetric analysis (TGA) showed an improvement in the thermal stability of LLDPE due to the introduction of crosslinking reactions. Results from Fourier Transformed Infrared Spectroscopy (FTIR) provided evidence for VTMS grafting onto LLDPE and subsequent crosslinking reaction.

A formation mechanism of guava-like polymer/SiO 2 nanocomposite particles (NCPs) in in situ emulsion (co) polymerization systems based on the enhanced homogenous nucleation was proposed in the present paper. The reactive 3-(trimethoxysilyl) propyl methacrylate modified SiO 2 nanoparticles (NPs) were chemically linked to form a large amount of SiO 2 clusters at the beginning of polymerization. The formation of the SiO 2 clusters driven by highly efficient grafting reaction of monomers to SiO 2 NPs could be regarded as an enhanced homogenous nucleation process. The SiO 2 clusters functioned as the main polymerization loci to form guava-like polymer/SiO 2 NCPs in the following polymerization process. The morphological evolution of the polymer/SiO 2 NCPs, and the role of the grafting reaction and nucleation pattern in the formation of the guava-like polymer/SiO 2 NCPs were systematically investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • An integrated anti-mould treatment of bamboo was effectively established. • Nearly no mould could grow on the modified bamboo with high hydrophobicity under investigation. • Relationships between anti-mould capacity and bamboo properties were summarized. The poor solubility of thymol restricts laccase catalytic efficiency for enhancing bamboo durability against exogenous mould. Herein, an integrated process of bamboo modification was established to improve the anti-mould capacity of bamboo through alkaline extraction and laccase-mediated thymol modification. The results showed that increased thymol dosages from 0 to 10.0% could significantly extend mould resistance activity persistence under laccase catalysis. Nearly no moulds could be found on the L-0.25Thy surface through the integrated strategy under a 30-day mould resistance test. The surface hydrophobicity of the modified bamboo increased from 52.5° to 123.5° due to various extents of thymol fixation. Multiple characterisation methods were employed to better grapple with the modified bamboo's chemical changes. This work demonstrates the complex dependence of improving the anti-mould capacity of bamboo through sequential alkaline extraction and laccase-mediated thymol modification to unlock the potential avenue to bamboo preservation. [ABSTRACT FROM AUTHOR]

Monomer casting (MC) nylon-6 was a polymeric modified by grafting 4-amion-2,2,6,6-tetramentylniperidine (TEMP) as reactive-hindered amine onto its chain so as to improve the compatibility and stability of the stabilizer in the polymer matrix. The structure of the reactive stabilizer was confirmed by Fourier transform infrared and proton nuclear magnetic resonance spectroscopic analyses. The effect of TEMP on the thermal stability of MC nylon-6 was studied. It was found that with the increase in TEMP dosage, the thermal weight loss of the samples first decreased and then increased and the preferred dosage of TEMP was about 0.2 mol%. The residual weight percentage (R) of all the samples decreased with heating time, and it does much more slowly for the grafting sample than that of pure one. The thermal degradation characteristic temperatures of MC nylon-6 were improved by grafting TEMP. The long-term aging of MC nylon-6 indicated that the carboxylic acid concentration of the grafting sample was lower than that of the pure sample, and its end amine group concentration was relatively higher during the whole aging process, presenting more stable chemical structure. Ultraviolet absorption and gel content of MC nylon-6 were also reduced by grafting TEMP. The crystallinity (Xc) of MC nylon-6 increased, and the crystallization growth rate and melt temperature (Tm) decreased with aging time, resulting from the annealing process at high temperature and the small molecular products during aging. [ABSTRACT FROM AUTHOR]

Enzymatic oxidation of tyrosine side-chains in proteins could produce reactive o-quinones that might subsequently react with the primary amino groups of functional compounds, which provided a worthwhile reference for functionalization of fibrion materials. In the present work the potential for using tyrosinase to graft the bovine lactoferrin onto Bombyx mori silk fibroin was examined. Lactoferrin could adsorb onto silk fibers and covalently bind to the previous enzymatically oxidized fibroin surface. The enzyme-generated quinones in silk fibers also might cause self-crosslinking of fibroin peptides, which led to beneficial changes of silk properties. For the fabric treated with tyrosinase and lactoferrin slight improvements of dyeability and strength were obtained in comparison to the control. The combinedly treated fabric showed encouraging resistance to S. aureus and E. coli, the antibacterial activities reached to 87.0 % and 76.4 %, respectively. The durability of the antibacterial silk was noticeably higher than that of the sample treated with lactoferrin alone. [ABSTRACT FROM AUTHOR]

A series of azobenzene-containing side-chain poly(ether sulfone)s (azo-PES) with various spacer lengths (2, 6 or 12 methylene units) were successfully synthesized via a nucleophilic substitution grafting reaction between poly(ether sulfone)s with hydroxylphenyl side groups and azobenzene monomers. Their chemical structures and properties were characterized by means of IR, UV–vis and 1H NMR. These azo-polymers show good thermal stability with glass transition temperatures and 5% weight-loss temperatures above 119 °C and 347 °C, respectively. The results of photoisomerization experiments indicated that azo-PES polymer with longer spacers correspond to higher photoisomerization rates. Upon irradiation with a 532 nm neodymium doped yttrium aluminum garnet (Nd:YAG) laser beam, they presented remnant values of birefringence larger than 82% of the saturation value of birefringence, indicating the good stability of the photoinduced orientation. No fatigue phenomena have been observed after several cycles of inscription–erasure–inscription sequences. [ABSTRACT FROM AUTHOR]

The grafting reaction of sulfonic acid - β - cyclodextrin (sulfonic acid - β - CD) and wool fabrics are similar to acid dyestuff dye wool, namely negatively charged amino sulfonic wool ionic bonding so that it is grafted onto the fabric. The experiments study the affecting grafting yield factors and get optimum process through univariate analysis; the concentration of sulfonic acid - β - CD 100 g/L, water bath temperature of 95 °C, reaction time 60 min, the concentration of acetic acid 5 g/L. At this point, the weight gain is 4. 35% . By infrared spectroscopy scanning, scanning electron microscopy and tests for washing fastness, verify that the sulfonic acid - β - CD grafted on to the fabric in the way of chemical cross-connection. [ABSTRACT FROM AUTHOR]

Abstract: The graft copolymerization of eucalyptus lignosulfonate calcium (HLS-Ca) from hardwood and acrylic acid (AA) was investigated by using Fenton agent as a coinitiator. The influences of reaction conditions on grafting parameters i.e. product yield (Y%), AA conversion (C%), grafting ratio (G%) and grafting efficiency (GE%) were carefully studied. The effects of the phenolic hydroxyl (Ph-OH) group on the polymerization of AA and grafting reaction were researched. Graft copolymers were identified by the new absorption at 1727cm−1, more homogenized morphology and higher decomposition temperature after grafted with AA, as illustrated in FTIR, SEM and TG spectra. The optimum synthesis conditions are as follows: H2O2 =25.2mol/L, FeCl2 =63.0mol/L, T =50°C and t =2h and the optimum percentages of Y, C, G and GE are 97.61%, 95.23%, 71.29% and 78.85%, respectively. The Ph-OH group of HLS-Ca cannot inhibit the polymerization of AA and is involved in the grafting reaction as an active center. [Copyright &y& Elsevier]

Abstract: The poly(3-hydroxybutyrate)(PHB)/poly(ethylene glycol)(PEG) grafting copolymer was successfully prepared by PHB and acrylate groups ended PEGM using AIBN as initiator. The crystallization behavior, thermal stability and environmental biodegradability of PHB/PEG grafting copolymers were investigated with differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and Biodegradation test in vitro. In the results, all the grafting copolymers were found to show the X-ray diffraction arising from the PHB crystal lattice, while none of the PEG crystallized peaks could be found even though the graft percent reached 20%. This result indicated that PEG molecules were randomly grafted onto PHB chain. The thermal properties measured by DSC showed that the melting temperature(T m) and glass transition temperature (T g) were both shifted to lower temperature with the graft percent increasing, and this broadened the narrow processability window of PHB. According to TGA results, the thermal stability of the grafting copolymers is not changed compared to pure PHB. From the biodegradation test, it could be concluded that degradation occurred gradually from the surface to the inside and that the degradation rate could be adjusted by the PEG grafting ratio. In another words, the biodegradation profiles of PHB/PEG grafting copolymer can be controlled. These properties make PHB/PEG grafting copolymer have promising potential applications especially in agriculture fields. [Copyright &y& Elsevier]

Dimer acid (DA) was grafted onto lignin (EHL) to form a graft copolymer DA-g-EHL. The selection of the reaction type and the optimization of the reaction conditions for the grafting reaction were conducted through orthogonal and single factor experiments. FT-IR and thermal analysis were used to characterize the graft product. It was found that, compared with free radical grafting, DA can be grafted onto EHL more effectively by ester condensation with strongly acidic cation exchange resin as a catalyst. Under optimum reaction conditions, the increase of acid value and the yield of graft copolymer can reach about 9.3% and 83%, respectively. The application of DA-g-EHL in preparing modified phenolic aldehyde amine curing agent (PAA) was studied. Results showed that the flexibility of the epoxy resin cured by DA-g-EHL modified PAA is significant higher than that of the resin cured by EHL modified PAA. The graft of DA onto EHL may reduce the rigidity of EHL and the chain stiffness of the PAA modified by EHL. [ABSTRACT FROM AUTHOR]

For increasing the compatibility of polystyrene (PS) and polyolefin elastomer (POE) blends, a Lewis acid catalyst, aluminium chloride (AlCl3), was adopted to initiate the Friedel-Crafts alkylation reaction and induce the formation of PS-graft-POE copolymer. The dynamic mechanical and rheological tests were used to study the effects of catalyst content on the miscibility and rheological behaviors. The results showed that the viscosity increased and the MFI decreased with the increase of the catalyst content. However, when the catalyst content was overmuch, the viscosity decreased and the MFI increased. The variety of miscibility and rheological behaviors of PS/POE blends was the results of the competition between in situ graft reaction and decomposition of blending compounds. [ABSTRACT FROM AUTHOR]

Abstract: The covalent modification of fullerene-C60 (C60) with poly(4-diphenylaminostyrene) (PDAS) was examined to explore the possibility of preparing new materials for effective photovoltaic cells. The high nucleophilicity and small steric hindrance of the PDAS carbanion is a very important factor in the addition of poly(4-diphenylaminostyryl)lithium (PDASLi) to C60. C60 end-capped PDAS (C60-PDAS), consisting of one PDAS molecule bonded to one C60 molecule at the polymer chain-end, was successfully prepared from the PDASLi/N,N,N’,N’-tetramethylethylenediamine system and C60. UV/vis and photoluminescence spectra suggest that C60-PDAS has considerable potential for the preparation of effective photovoltaic cells. [Copyright &y& Elsevier]

Abstract: The grafting reaction of poly(N-vinylcarbazolyl)lithium (PNVCLi) with tert-butyllithium onto fullerene-C60 (C60) was examined to explore the possibility of preparing new materials for effective photovoltaic cells. When the molar ratio of C60/Li was over four, the grafting reaction products obtained were completely soluble in tetrahydrofuran. The number-average molecular weight of the grafting reaction products obtained was greater than that of the respective parent PNVCs, indicating the formation of PNVC with a C60 end-group. Gel permeation chromatography and 13C NMR analyses showed that the product of the grafting reaction was C60 bonded to PNVC and t-butyl groups. UV/vis and PL spectra suggested that this PNVC may be useful for preparing effective photovoltaic cells. [Copyright &y& Elsevier]

Abstract: Y zeolite containing well-dispersed iron (Fe/Y–G) was prepared by grafting reaction of the ferrocene molecule (Cp2Fe) on the acidic sites of HY zeolite followed by thermal treatment in oxygen. In situ FTIR and chemical analysis revealed that Cp2Fe molecule adsorbed on the zeolite surface lost one cyclopentadienyl group leading under vacuum at 423K to the formation of a surface iron-cyclopentadienyl complex. Fe/Y–G was then obtained by calcination at 773K in flowing oxygen. This solid was characterized by XPS, XAFS, CO adsorption FTIR, UV–vis DRS, and catalytic oxidation reaction of CO with oxygen. The characteristic oxygen-to-metal charge-transfer transition bands at ca. 215nm and 250nm showed existence of Fe3+ of Fe/Y–G in isolated tetrahedral sites. Both the 2P3/2 and 2P1/2 electron binding energies of iron and the Fe K edge energy were higher than those of Fe2O3, suggesting that the iron ions contained in Fe/Y–G were highly dispersed and had higher spin-orbital splitting, due to the hybridization of iron 4p atomic orbitals with partly 3d molecular orbitals. The Fe/Y–G showed only one ν(CO) infrared adsorption band at 2194cm−1, very different from a Fe/Y–I sample prepared by impregnation with FeCl3. The Fe/Y–G zeolite showed a higher catalytic activity in the oxidation of carbon monoxide with molecular oxygen than the Fe/Y–I sample. This behavior was ascribed to the special coordination geometry and electronic structure of the iron atom in the zeolite. [Copyright &y& Elsevier]

Abstract: Grafting reactions of polybutadiene with macro peroxy initiators and postpolymerization were studied. The cationic polymerization of tetrahydrofuran (THF) initiated by the cationic species derived from bis-(4-bromomethylbenzoyl) peroxide (BBP) or bis-(3,5-dibromomethylbenzoyl) peroxide (BDBP) gave the PTHF macroperoxy initiator (MPI). PTHF-b-PMMA macroperoxy initiator (MPIb) was also obtained by the redox polymerization of methyl methacrylate initiated with the hydroxyl ends of PTHF and Ce(IV) salts without decomposing the peroxide groups in the middle. Macroperoxy initiators thermally grafted on cis-polybutadiene (PBD) with thermal curing to yield graft copolymers containing crosslinked and soluble parts, which were separated by the sol–gel analysis. FTIR spectra of the crosslinked samples indicated the characteristic signals of the PTHF, PBD and PMMA blocks. The crosslinked copolymers decomposed at around 470°C. Postpolymerization of the crosslinked products indicated the increase in crosslinking density which has been followed by measuring the gradual increase of swelling values. Postpolymerization crosslinking was estimated as a first order reaction rate. [Copyright &y& Elsevier]

Abstract: A nanocomposite possessing perovskite-related nanosheets dispersed in a siloxane network was prepared by cohydrolysis of the n-decoxy derivative of an ion-exchangeable layered perovskite, HCa2Nb3O10·xH2O (HCaNb), and tetramethoxysilane (TMOS) via a sol–gel process involving exfoliation. In the X-ray diffraction (XRD) pattern of the product after drying for 1d, the (00 l) reflections disappeared. The transmission electron microscopy (TEM) image of the product after drying for 1d showed dark lines with a thickness of 1.5nm, which was consistent with the thickness of an individual nanosheet, indicating exfoliation of HCaNb. In the XRD patterns of the reaction products of the n-decoxy derivative of HCaNb and TMOS before drying and after drying for 60min, (00 l) reflections were detected. After drying for 80min, the intensity of the (00 l) reflections decreased. The intensity decreased with an increase in the drying time, indicating that the exfoliation of HCaNb occurred during the drying process. [Copyright &y& Elsevier]

Abstract: Novel waterborne polyester polyurethane (WPU) was synthesized and firstly applied to dispersion polymerization of styrene (PSt). Monodisperse PSt particles were successfully prepared by radiation-induced dispersion polymerization, after dispersed in ethanol–water medium and stabilized by WPU at room temperature. The conversion–time curve was investigated, and the grafting reaction between WPU and PSt was investigated via FT-IR, XPS and 1H NMR spectrum. Furthermore, the grafting efficiency of WPU (GWPU, ratio of grafted WPU versus the total content of WPU in the system) was calculated via 1H NMR spectrum. It shows when vinyl groups are attached to WPU molecules, the diameter of PSt particles decrease. [Copyright &y& Elsevier]

Abstract: A new material has been synthesised by reaction between a calix[4]arene amine derivative and an oxidized activated carbon in DMF. Each reactant was characterized by thermogravimetric analysis (TGA) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). In addition, the BET surface area of activated carbon, oxidized carbon and calixarene-modified carbon, were measured and are equal to 737, 519 and 351 m2/g, respectively. Results show that calixarene is linked to superficial oxygen functional groups through a covalent bond. A percentage of grafted calixarene of the order of 35% have been calculated from the results of elemental analysis. [Copyright &y& Elsevier]

Abstract: Tetraalkyltin complexes, SnR4 (R=Me, Et, Pr, Bu) could react with Pt/HY at 193, 243, 273 and 333K, respectively. The reactions occurred on the surface of the zeolite and the organotin grafted zeolites were characterized in detail. The framework and the microporous structure of the grafted Pt/HY zeolites were retained. However, the modified zeolites showed better size selectivity in the absorption of hydrocarbons. [Copyright &y& Elsevier]

Abstract: The grafting reaction of SnMe4 on the surface of Hβ zeolite (Si/Al=25.0) was studied under high vacuum conditions. The chemical compositions and structure of the resulting solid were characterized by in situ FTIR, ICP, XRD, XPS, 13C and 119Sn MAS NMR, UV–Vis DRS, gas phase chromatogram (GC), chemical analyses, temperature programmed decomposition (TPD), temperature programmed reduction (TPR), and N2 adsorption at low temperature. The results showed that SnMe4 reacts with Hβ zeolite quantitatively at temperature as low as 183K and the reaction occurred on the surface of the zeolite without destroying the framework of zeolite. The BET surface area and the pore volume of the zeolite decreased and the surface properties changed, however the microporous structure was retained upon the reaction and post treatment. [Copyright &y& Elsevier]

Grafting reaction of methyltriethoxysilane on sepiolite surface was studied. The structure of the salinized product before and after thermal treatment was characterized by XRD, TG-DTA, SEM and IR. It is found that the silicon monomers are grafted on the external surface of sepiolite via silicon hydroxyls. The thermal stability remains unchanged after silanization. [ABSTRACT FROM AUTHOR]