新型三元互穿聚合物网络阻尼材料的研制

采用平衡溶胀工艺,合成了具有宽温域、高阻尼值的新型三元互穿聚合物网络.透射电镜证明了乳液交联反应的发生和互穿网络的结构.分别通过对乳液及乳胶膜性能的测试和比较,发现三元互穿聚合物网络相容性和阻尼性均优于二元互穿聚合物网络.     

胶乳型互穿网络聚合物的研究

综述了胶乳型互穿网络聚合物的研究,着重介绍了合成工,乳胶粒形态结构的影响因素,同时亦对胶乳型互穿网络聚合物的性能作了介绍。     

聚氨酯—聚丙烯酸酯互穿聚合物网络的转变行为

互穿聚合物网络(IPN),是指由两种或多种各自交联(或其中一种交联)且相互穿透、缠结的高分子共混物。理想的IPN呈现不同网络在分子水平的互穿,而实际的IPN则呈现相分离结构,互穿网络主要发生在相界面上。网络之间的互穿给材料带来某些性     

聚苯乙烯/聚丙烯酸丁酯自交联胶乳互穿聚合物网络的力学性能和动态力学性能

采用种子乳液聚合制备了聚苯乙烯/聚丙烯酸丁酯自交联胶乳互穿聚合物网络。拉伸实验结果表明,用双丙酮丙烯酰胺和己二酸二酰肼自交联的胶乳互穿聚合物网络(LIPN)比相应的胶乳互穿聚合物网络具有较高的拉伸强度,并且随双丙酮丙烯酰胺用量的增加,拉伸强度增加以及永久变形降低,但离子键和氢键交联的LIPN具有很高的扯断伸长率和很大的永久变形,这些说明用双丙酮丙烯酰胺和己二酸二酰肼界面共价键交联能很好地改善力学性能和抗蠕变性能。动态力学谱结果表明,用双丙酮丙烯酰胺和己二酸二酰肼交联的LIPN比相应的LIPN以及离子键和氢键交联的LIPN具有较好的组分相容性和阻尼性能。     

互穿聚合物网络阻尼材料研究进展

介绍了互穿聚合物网络阻尼材料的研究进展，讨论了对其阻尼性能的评价以及组分、组分间的相容性、交联密度、无机填料等影响性能的因素，并展望了互穿聚合物网络的研究前景。     

用原子转移自由基聚合法制备SBS/聚(苯乙烯-甲基丙烯酸丁酯)互穿聚合物网络

将线型热塑性弹性体SBS溶胀于苯乙烯和甲基丙烯酸丁酯混合液中，以BPO为引发剂，在CuCl/2,2′－联吡啶酯位化合物催化下进行原子转移自由基聚合，制备了SBS／聚（苯乙烯－甲基丙烯酸丁酯）互穿聚合物网络。结果表明，实现了苯乙烯－甲基丙烯酸丁酯共聚物的可控聚合，聚合物数均相对分子质量随单体转化率的提高呈线性增长，且分布较窄，从而得到了组成和性能不同的互穿聚合物网络。     

阻尼乳胶涂料

以苯乙烯－丙烯腈共聚物为“核”,丙烯酸正丁酯－丙烯酸乙酯共聚物为“壳”,合成了具有互穿聚合物网络结构的乳胶,测定了该乳胶配制的涂料性能及其在阻尼领域的实际应用效果。     

非线性光学聚合物材料新进展

本文综述了非线性光学聚合物材料新进展，探讨了光折变聚合物材料、交联极化聚合物材料、互穿聚合物网络等在非线性光学材料中的应用范围。     

EA／St—AN互穿聚合物网络的加工和力学性能

以丙烯酸乙酯为软单位，苯乙烯和丙烯腈为硬单体，二乙烯基苯或三乙二醇双丙烯酸酯为交联剂，采用多步种子乳液聚合技术制备了半互穿和全互穿聚合物网络，研究了软、硬单体配比，交联剂用量，加工次数对共聚物流变行为、力学性能和结构形态的影响。结果表明，制备的半互穿和全互穿聚合物网络均可在适宜的条件下流动成型。如果配方选择适当，反复加工后力学性能基本不变。     

国内外化工简讯

新型的墙壁装饰材料问世由湘潭大学化学系钟以诚副教授和省维尼伦厂陈集和、顾仁安等合作完成的丙烯酸系互穿网络聚合物乳液(简称IPN乳胶)和丙烯酸系互穿网络聚和物乳胶涂料(简称IPN乳胶涂料)两项科研成果于最近通过了省科委的技术鉴定。     

Highly toughened poly(lactic acid) blends prepared by reactive blending with a renewable poly(ether-block-amide) elastomer

Renewable poly(ether-block-amide) (PEBA) elastomer was grafted with glycidyl methacrylate (GMA) to prepare PEBA-GMA, then it was melting blended with poly (lactic acid) (PLA) in an effort to achieve fully bio-based super-toughened PLA materials. The notched Izod impact strength of PLA/PEBA-GMA blend was significantly enhanced when the content of PEBA-GMA was higher than 20 wt%, and the tensile toughness was also improved. It was found a new copolymer was formed at the interface due to the reaction of the end groups ( OH,  COOH) of PLA with the epoxide group of PEBA-GMA. This greatly improves the interfacial adhesion between PLA and PEBA-GMA component, leading to finer dispersed particles of PEBA-GMA which were better wetted by the PLA matrix. Therefore, the highly enhanced notched impact strength was ascribed to the effective reactive compatibilization promoted by the interfacial reaction. This provides a new idea for preparing super tough PLA materials with bio-based elastomer, which will widely extend the application of PLA.     

Processability,property, and morphology of biodegradable blends of poly(propylene carbonate) and poly(ethylene‐co‐vinyl alcohol)

Biodegradable blends of poly(propylene carbonate) (PPC) and poly(ethylene‐co‐vinyl alcohol) (EVOH) were melt compounded in a batch mixer followed by compression molding. The processability, mechanical properties, thermal behavior, and morphologies of the blends were investigated with torque rheometer, Fourier transform infrared spectroscopy, tensile tests, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Torque rheometry indicated good interfacial miscibility between PPC and EVOH phases, and then fourier transform infrared spectroscopy spectra demonstrated that a certain extent of hydrogen‐bonding interactions between PPC and EVOH matrix in the blends. A study of the mechanical properties and thermal behavior showed that the EVOH incorporation can significantly enhance the tensile strength, thermal stability, and crystallinity of the blends. Moreover, dynamic mechanical analysis and differential scanning calorimetry both revealed that PPC and EVOH were compatible to some extent. Further, scanning electron microscopic examination also revealed the good interfacial adhesion between EVOH and PPC phases. POLYM. ENG. SCI., 47:174–180, 2007. © 2007 Society of Plastics Engineers     

Synergetic toughening of poly(phenylene sulfide) by poly(phenylsulfone) and poly(ethylene-ran-methacrylate-ran-glycidyl methacrylate)

Poly(phenylene sulfide) (PPS) is a high-performance super-engineering plastic, but is brittle. In this study, super-tough PPS-based blends were successfully generated by melt blending PPS with poly(ethylene-ran-methacrylate-ran-glycidyl methacrylate) (EGMA) and poly(phenylsulfone) (PPSU) at (56/14/30) PPS/EGMA/PPSU composition, and their toughening mechanisms were investigated in detail. It was demonstrated the interfacial reaction between PPS and EGMA and partial miscibility between PPS and PPSU, both play important synergistic roles on the toughening. The interfacial reaction between PPS and EGMA contributes to the reduction of the PPSU domain size by the increased viscosity of the PPS matrix containing EGMA, and the increased mobility of EGMA chains by negative pressure effect. The partial miscibility between PPS and PPSU contributes to the increased interfacial adhesion between PPS and PPSU, resulting in effective propagation of the impact to the domains, and the increased mobility of not only PPSU chains but also PPS chains, causing a reduction in crystallization.     

A study of poly vinyl chloride / poly(butylene adipate-co-terephthalate) blends

Polymer blends were prepared by melt blending technique using poly vinyl chloride (PVC) and poly(butylene adipate-co-terephthalate) (PBAT). Different ratios of the blends were studied to investigate their mechanical, thermal and morphological properties. The FTIR spectrum indicated a slight increase of frequencies at C = O peak from 1714 to 1718 cm^-1 indicating a chemical interaction between C = O of PBAT and α-hydrogen of PVC. The tensile properties of PVC/PBAT blends highest at weight ratio of 50/50. The dynamic mechanical analysis (DMA) result proves that PVC and PBAT formed a miscible system with one glass transition temperature (T_g). The incorporation of PBAT results in a gradual decrease of the viscosity (loss modulus) and an increase of elasticity (storage modulus). The thermal properties of blend show the decomposition temperature of PVC in the blend decrease with the addition of PBAT. Scanning electron micrograph shows good interfacial adhesion on the tensile fractured surface of PVC/PBAT blend, which played important roles in enhancing the mechanical properties (strength and modulus).     

Effects of phase separation on the mechanical properties of polystyrene/poly(vinyl methyl ether) blends

The effects of phase separation temperature and time on the tensile, dynamic mechanical, and tear properties of blends of polystyrene and poly(vinyl methyl ether) were investigated after phase separation above their respective cloud points with specified temperature-annealing time protocols. The results are analyzed in terms of the phase connectivity, interfacial adhesion, and changes in the glass transition temperature.     

Acoustic emission during irreversible deformation in short fiber reinforced poly(vinyl chloride) composites

Acoustic emission (AE) during irreversible deformation in short glass fiber reinforced poly(vinyl chloride) (PVC) composites was studied using a piezoelectric crystal transducer. Compared to the well-coupled composites, many more AE events were observed during tensile deformation in the poorly-coupled composites, presumably due to failure at the fiber-matrix interface. No fiber fracture was detected in the tensile tests for either well-coupled or poorly-coupled composites. Irreversibility of acoustic emission was observed in repeated tensile loading experiments. Unlike PVC, the short fiber composites fractured during stress relaxation at 1 percent elongation. Studies of acoustic emission behavior during stress relaxation indicated that interfacial debonding is a time-dependent process. Relaxation fracture time was strongly increased by chemical coupling at the interface.     

Fabrication of poly(lactic acid)/graphene oxide/stearic acid composites with improved tensile strength

For the purpose of the development of poly(lactic acid)/graphene oxide composites with improved tensile properties, a stearic acid compatibilizer was used to enhance the compatibility of the graphene oxide sheets with the poly(lactic acid) polymer matrix. Graphene oxide was modified with stearic acid at different mass ratios of 1:1, 1:3, and 1:5 prior to forming the composites with poly(lactic acid). Characterization showed positive effects of stearic acid attached to GO in every mass ratio and also enhanced compatibility with the poly(lactic acid) matrix. Stearic acid could strengthen the interfacial interactions between the flat graphene oxide sheets and the poly(lactic acid) matrix resulting in improved tensile strength. The tensile strength of the poly(lactic acid)/graphene oxide/stearic acid composite with a mass ratio of graphene oxide and stearic acid 1:1 increased by 32% compared to poly(lactic acid) alone. Based on these results, the graphene oxide/stearic acid composites show potential for use as nanosheet fillers for tensile strength enhancement in poly(lactic acid). POLYM. COMPOS., 38:2272–2282, 2017. © 2015 Society of Plastics Engineers     

Effect of processing methods and functional groups on the properties of multi-walled carbon nanotube filled poly(dimethyl siloxane) composites

Pristine and functionalized multi-walled carbon nanotubes (MWCNTs) filled poly(dimethyl siloxane) (PDMS) composites were produced by two different methods, namely the solution mixing method and the mini-extruder method. The composites produced using the mini-extruder exhibit relatively higher tensile strength and higher thermal conductivity due to better nanotubes dispersion. On the other hand, the composites prepared via solution mixing have higher electrical conductivity and better thermal stability due to the high aspect ratio of nanotubes. Scanning electron micrographs of composites fracture surface revealed that composites produced by mini-extruder resulted shorter nanotube length, thus lowering the aspect ratio of MWCNTs. In general, functionalization of nanotubes increases the tensile strength, thermal conductivity, and thermal stability of the PDMS composites due to the improved interfacial adhesion and nanotubes dispersion.     

Effect of acrylonitrile content of acrylonitrile butadiene rubber on mechanical and thermal properties of dynamically vulcanized poly(lactic acid) blends

We report here the morphology, thermal and tensile properties of poly(lactic acid) (PLA) blends composed of acrylonitrile butadiene rubber (NBR) with different acrylonitrile contents with/without dynamic vulcanization by dicumyl peroxide (DCP). The interfacial tension of PLA and NBR measured by contact angle measurement decreased as the acrylonitrile content of NBR decreased. Likewise, SEM images showed that the rubber particle size reduced with decreasing acrylonitrile content owing to the stronger interfacial adhesion between the PLA matrix and NBR domains. Incorporation of DCP at 1.0 phr for dynamic vulcanization led to higher crosslink density and, in turn, optimal tensile strength and tensile toughness as a result of the action of PLA‐NBR copolymer as a reactive compatibilizer. The dynamic vulcanization of the blends containing low acrylonitrile NBR gave the most improved tensile properties because the free radicals from DCP decomposition preferentially attacked the allylic hydrogen atoms or double bonds of the butadiene backbone. Accordingly, more NBR macroradicals were generated and probably more PLA‐NBR copolymers were produced. Moreover, further addition of DCP at 2.0 phr provided a large amount of crosslinked NBR gel, which significantly degraded the tensile properties. From the DSC results, dynamic vulcanization lowered the cold crystallization temperature, implying an improvement of cold crystallization. Finally, TGA results showed a higher degradation temperature as a function of DCP content, which suggested that thermal stability increased due to stronger interfacial adhesion as well as higher gel content. © 2019 Society of Chemical Industry