改性聚乙烯泡沫塑料的配方和生产技术

论述了改性聚乙烯泡沫塑料的配合技术、成型工艺及常见质量问题的分析。着重讨论了改性聚乙烯泡沫塑料3类改性剂(树脂类、热塑性弹性体类、橡胶类)的改性效果,并结合实际阐述了聚乙烯泡沫塑料的应用。     

国内聚乙烯接枝和交联改性的研究进展

综述了国内聚乙烯接枝改性和交联改性技术的最新进展。     

辐射技术在聚乙烯改性的研究进展

聚乙烯(PE)是用途非常广泛的通用塑料,具有优良的韧性、耐化学性和良好的加工性能,但耐热性能差,非极性和极低表面能等缺点限制了它的使用。辐射技术可以有效地改善聚乙烯的耐热性、提高聚乙烯的极性,拓展其应用领域。从辐射交联、辐射接枝和辐射增容三个方面综述了辐射技术在聚乙烯改性加工的应用研究进展。今后不断加强无污染、无公害的辐射技术在聚乙烯加工改性的开发和应用。     

聚乙烯粉末涂料的改性研究

采用熔体复合技术制备了纳米TiO2改性聚乙烯粉末涂料，测定了其熔体流动速度，力学性能，涂膜性能和纳米TiO2粒子的分散性。采用该技术还制备了马来酸酐接枝改性聚乙烯粉末涂料，测定了其力学性能和接枝率。研究结果表明：纳米TiO2改性聚乙烯粉末涂料中的纳米粒子达到了纳米级分散。在提高涂膜力学性能的同时，明显改善了涂膜的柔韧性和流平性；马来酸酐接枝改性聚乙烯粉末涂料通过在聚乙烯主链上引入极性基团。在提高涂膜力学性能的同时，也提高了其对底材的附着力。     

我国氯化聚乙烯的研究进展

综述了近年来我国氯化聚乙烯(CPE)的技术进展及改性研究,介绍了氯化聚乙烯的生产现状及市场需求,指出了我国氯化聚乙烯的发展方向。     

不同维度纳米填料改性氯化聚乙烯橡胶的研究进展

综述纳米二氧化硅、碳纳米管、石墨烯等多种不同维度纳米填料改性氯化聚乙烯橡胶的研究进展。介绍利用不同填料改性氯化聚乙烯橡胶的机理及改性后氯化聚乙烯橡胶的应用概况,提出不同填料改性氯化聚乙烯橡胶的性能优化和应用的展望。     

超高分子量聚乙烯的改性

概述了近年来超高分子量聚乙烯(UHMWPE)改性技术所取得的进展,并简单地介绍了改性的原理和应用。     

丙烯酸固相接枝制备高稳定性改性聚乙烯蜡微乳液

旨在对低密度聚乙烯蜡进行化学接枝改性,改善其可乳化性能,从而制备高稳定性改性聚乙烯蜡微乳液。首先以丙烯酸作为接枝单体,采用悬浮溶胀接枝法对低密度聚乙烯蜡进行化学接枝改性;然后,通过选取适当的阴离子乳化剂和非离子乳化剂的复配体系,对接枝改性的聚乙烯蜡产物进行乳化。结果表明：采用SDS和Tween80等比例复配,控制乳化温度为90～95℃,乳化剂用量为聚乙烯蜡的10%、乳化时间为30min时,采用相转变乳化法可制得高稳定性的聚乙烯蜡微乳液。采用FTIR对改性聚乙烯蜡进行了结构表征,证明了丙烯酸被成功地接枝到了聚乙烯蜡分子上,并通过DSC分析研究了其熔点和结晶情况的变化：聚乙烯蜡的熔点为102.41℃,丙烯酸接枝改性聚乙烯蜡的熔点为102.85℃;改性聚乙烯蜡与未改性的聚乙烯蜡的比结晶度为77.7%。     

聚乙烯改性的研究进展

综述聚乙烯的主要特性及分类,介绍聚乙烯的改性,包括填充、共混、接枝、交联以及改性后的应用情况,并指出今后聚乙烯改性的发展方向。     

聚乙烯管材的应用及降解行为的发展

聚乙烯管是以聚乙烯为原材料通过挤出成型而得的塑料管材产品。聚乙烯管在输送燃气和给排水方面具有广泛应用。综述了国内外关于聚乙烯管在燃气管和给排水管领域、加油站和核电站领域的应用及其降解行为的探索,并简要介绍了提高聚乙烯管抗降解性能的两种改性方法:填充改性和交联改性。研究表明,通过填充改性发挥无机物和有机物的协同作用和通过交联改性引入新的官能团均可有效提高聚乙烯管的抗降解性能。可以预期聚乙烯管将继续在多个领域有新的应用,这对聚乙烯管的性能提出了新的要求,有必要进一步探索聚乙烯管的降解机理及提高其抗降解性能的新方法,如对聚乙烯同步进行物理改性和化学改性。     

Miscibility and interaction studies on some aqueous polymer blend solutions by ultrasonic and rheological techniques

The aqueous solutions of poly(ethylene oxide)–polyacrylic acid, poly(vinyl pyrrolidone)–poly(vinyl alcohol), and poly(ethylene oxide)–poly(vinyl alcohol) blends have been studied by ultrasonic, rheological, and viscometric techniques. Extensive investigation over a wide range of concentrations, temperatures, compositions, pH, and shear rates indicate the degree of miscibility, extent of interaction between the polymers, and stoichiometry of the polymer complexes formed by the strong interaction between the polymers in solutions. These investigations indicate the miscibility of poly(ethylene oxide)–polyacrylic acid and poly(ethylene oxide)–poly(vinyl pyrrolidone) blends and the immiscibility of poly(ethylene oxide)–poly(vinyl alcohol) blends in conformity with other reported investigations. © 1994 John Wiley & Sons, Inc.     

Blending Modification of PHBV/PBS/PEG and its Biodegradation

This study used poly(butylene succinate) and poly(ethylene glycol) to modify poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The results showed that the incorporation of poly(butylene succinate) and poly(ethylene glycol) improved the mechanical properties of blends. The results showed that crystallinity of the poly(ethylene glycol)-containing blends decreased, so do the crystallization temperature and melting temperature of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) component of blends. Poly(butylene succinate)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/poly(ethylene glycol) ratio of 50:20:30 was chosen owing to its good properties. The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) component of blends can be degraded completely by Pseudomonas mendocina DS04-T, whereas this strain cannot degrade poly(butylene succinate) and poly(ethylene glycol). Apart from poly(butylene succinate), Fusarium sp. FS1301 can also biodegrade poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(ethylene glycol).     

Properties of Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline Conductive Films: The Effect of Poly(ethylene glycol) Diglycidyl Ether

The effect of polyaniline and poly(ethylene glycol) diglycidyl ether on tensile properties, morphology, thermal degradation, and electrical conductivity of poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films was studied. The poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films were prepared using a solution casting technique at room temperature until a homogeneous solution was produced. Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline/poly(ethylene glycol) diglycidyl ether conductive films exhibit higher electrical properties, tensile strength, modulus of elasticity but lower final decomposition temperature than poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films. Scanning electron microscopy morphology showed that the polyaniline more widely dispersed in the poly(vinyl chloride)/poly(ethylene oxide) blends with the addition of poly(ethylene glycol) diglycidyl ether as surface modifier.     

PEALT三元共聚酯的制备及其性能研究

通过聚对苯二甲酸乙二醇酯(PET)、聚己二酸乙二醇酯(PEA)、聚L-乳酸(PLLA)3种低聚物熔融缩聚反应制备聚(对苯二甲酸乙二醇酯-己二酸乙二醇酯-乳酸)(PEALT)共聚酯。采用核磁共振仪(~1H-NMR)、差示扫描量热仪(DSC)、热重分析仪(TGA)和广角X射线衍射仪(WAXD)等测试技术对共聚酯进行了表征。     

Effect of alkali on filaments of poly(ethylene terephthalate) and its copolyesters

The alkali hydrolysis of poly(ethylene terephthalate), anionic copolymer of poly(ethylene terephthalate), and block copolymer of poly(ethylene terephthalate)–poly(ethylene glycol) is investigated under a variety of conditions of alkali concentration in aqueous bath, additives, time, and temperature. Measurements of loss in weight, linear density, breaking load, tenacity, elongation to break apart from intrinsic viscosity, fiber density, COOH-end group content, diameter of filaments, and scanning electron micrographs have been analyzed to identify the differences in the action of alkali on these polymer materials.     

Synthesis and characterization of poly(methylene disulfide) and poly(ethylene disulfide) polymers in the presence of a phase transfer catalyst

Poly(methylene disulfide) and poly(ethylene disulfide) were synthesized from the polycondensation of methylene dichloride and ethylene dichloride monomers, respectively, in the presence of benzyltriethylammonium chloride as a phase transfer catalyst. The structures of the synthesized polysulfides were confirmed via the elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy and X-ray diffraction techniques. Moreover, the thermal behaviors of synthesized poly(methylene disulfide) and poly(ethylene disulfide) were characterized using differential scanning calorimetry and thermogravimetric analysis methods. The synthesized poly(methylene disulfide) and poly(ethylene disulfide) have molecular weights of about 2262 and 2863 g/mol, respectively. In addition, the polymers have crystalline structures absorbed in the amorphous sections. However, the d-spacing of polymers’ crystalline parts was different. Moreover, poly(methylene disulfide) and poly(ethylene disulfide) have a two- and one-step degradation behavior, respectively.     

A study of mixtures of poly(ethylene oxide) with polystyrene or poly(styrene-co-acrylic acid) by inverse gas chromatography and viscosimetry

Summary Systems of poly(ethylene oxide)/polystyrene and of poly(ethylene oxide)/poly(styrene-co-acrylic acid) of different ratios were studied by inverse gas chromatography using benzene and n-decane as molecule probes and by viscosimetry in tetrahydrofuran. The transition temperatures as shown in the retention diagrams and the interaction parameters as determined by inverse gas chromatography and by viscosimetry showed that whereas poly(ethylene oxide) is incompatible with polystyrene, the introduction of amounts of acrylic acid groups into polystyrene chains by free radical copolymerization led to compatible systems of the acidic copolymer with the poly(ethylene oxide).     

Block copolymers comprising poly(ethylene oxide) and poly(hydroxyethyl methacrylate) blocks: synthesis and characterization

Monofunctional poly(ethylene oxide) macroinitiators with a molecular weight of 2000, 5000, 10?000, 20?000 and bifunctional poly(ethylene oxide) macroinitiators with a molecular weight of 20?000 were used for the atom transfer radical polymerisation (ATRP) of hydroxyethyl methacrylate (HEMA) in ethylene glycol as a solvent. The polymerisation proceeds in a controlled way up to high conversions. The molecular weight of the obtained copolymers increases linearly with conversion. A high rate of polymerisation was observed for the ATRP of HEMA. The effect of the poly(ethylene oxide) moiety on the course of the reaction is limited to solvating effects. The surface analysis of poly(ethylene oxide)/poly(hydroxyethyl methacrylate) block copolymers by means of atomic force microscopy in tapping mode using phase imaging shows phase separated domains with characteristic features related to the volume fraction of the respective blocks.     

Studies on syntheses and permeabilities of special polymer membranes. VI. Permeation characteristics of cellulose nitrate membranes and cellulose membranes

The permeation characteristics of cellulose nitrate membranes and cellulose membranes were investigated using aqueous solutions of poly(ethylene glycol) as feed. To gain cellulose membranes the nitro groups in cellulose nitrate were converted to hydroxyl groups. It was found that cellulose nitrate membranes separate poly(ethylene glycol) 6000 but not any cellulose membrane did separate poly(ethylene glycol) 20 000.     

Dye Sorption and Water Uptake Properties of Crosslinked Acrylamide/Sodium Methacrylate Copolymers and Semi-Interpenetrating Polymer Networks Composed of PEG

A series of novel semi-interpenetrating polymer networks hydrogels composed of poly(ethylene glycol) and random copolymer of acrylamide/sodium methacrylate were prepared by polymerization of aqueous solution of acrylamide, sodium methacrylate using ammonium persulphate/N,N,N′,N′-tetramethylethylenediamine as a redox-initiating pair in the presence of poly(ethylene glycol) and poly(ethylene glycol)diacrylate as crosslinker. Fourier Transform Infrared spectroscopy was used to identify the presence of different repeating units in the semi IPNs. Water uptake and dye-sorption properties of acrylamide/sodium methacrylate hydrogels and acrylamide/sodium methacrylate/poly(ethylene glycol) semi IPNs were investigated as a function of chemical composition of the hydrogels. Cationic dye, Janus Green B have been used in sorption studies as a model molecule. This study has given the quantitative information on the swelling and sorption characteristic of acrylamide/sodium methacrylate hydrogels and acrylamide/sodium methacrylate/poly(ethylene glycol) semi IPNs in many potential applications.