离聚体对PA1010／PS共混体系相形态及结晶的影响

采用ＳＥＭ,ＤＳＣ和偏光显微镜等方法研究了磺化聚苯乙烯及其锂盐,锌盐和钠盐（ＰＳ－ＮａＳ）;四种离聚体对ＰＡ１０１０／ＰＳ共混体系相形主结晶性能的影响。结果表明,对于ＰＡ１０１０／ＰＳ（８０／２０）共混体系,四种离聚体的增容效果依次按ＰＳ－ｎａＳ〈ＰＳ－ＺｎＳ〈ＰＳ〈ＺｎＳ〈ＰＳ－ＬｉＳ〈ＰＳ－ＨＳ的顺序递增,表明离聚体的离子交联能力越弱,其增容效果越好。四种离聚体中只有ＰＳ－ＺｎＳ对ＰＡ１０１０     

反应型增容剂PS-co-GMA在PA1010/ABS共混体系中的增容作用

以ＰＳ－ｃｏ－ＧＡＭ作为ＰＡ１０１０／ＡＢＳ共混体系的增容剂,探讨了增容剂的含量对共混体系力学性能的影响,同时,利用熔融共混法制备了ＰＡ１０１０／ＡＢＳ－ｇ－ＧＭＡ共混体系,比较了两种增容方式对共混体系力学性能的影响。     

SPS及其镧离聚物对PS/PBMA共混体系相容性的影响

通过运用溶液成膜共混法制备了系列聚苯乙烯／聚人烯酸丁酯（ＰＳ／ＰＢＭＡ）共混物。借助差示扫描量热法（ＤＳＣ）、傅里叶变换红外光谱（ＦＴＩＲ）、扫描电子显微镜９ＳＥＭ）研究了磺化磺苯乙烯（ＳＰＳ）及其离物对共体系相容性的影响。共混物中ＳＰＳ磺化度越高,ＰＢＭＡ相的下班伦为温度向高温方向移动越明显 。ＳＰＳ镧离聚物（ＳＰＳ１．８－Ｌａ）为增容剂时,ＤＣＳ结果显示共混物２相Ｔｇ靠扰;ＳＥＭ归咎显示２相分     

阻隔性HDPE／MPE／PA1010共混体系的研究

用挤出法以马来酸酐（ＭＡＨ）接枝高密度聚乙烯（ＨＤＰＥ）为增容剂（ＭＰＥ），ＰＡ１０１０为阻隔组分，ＨＤＰＥ为基料，制取了ＨＤＰＥ／ＭＰＥ／ＰＡ１０１０共混材料。研究了挤出温度、ＭＰＥ用量、ＰＡ１０１０含量对其阻隔性能的影响，比较了几种不同渗透体系的吸油率和渗透损失量。     

PA1010／PP—g—ATBS／PP共混体系的形态与性能

采有向向双螺杆杆挤出机制备了不同组成的ＰＡ１０１０／ＰＰ及ＰＡ１０１０／ＰＰ－ｇ－ＡＴＢＳ／ＰＰ的共混物。采用聚丙烯接枝丙烯酰胺基甲基丙烷磺酸共聚物（ＰＰ－ｇ－ＡＴＢＳ）作为增容剂来研究对ＰＡ１０１０／ＰＰ共混体系形态与力学性能的影响，研究不同增容剂含量对ＰＡ１０１０／ＰＰ共混物的力学性能，形态结构的影响。     

PVC／SBR热塑性弹性体的研制

以ＡＢＳ、氯丁橡胶（ＣＲ）、马来酸酐（ＭＡ）接枝ＳＢＲ（ＳＢＲ－ＭＡ）作增容剂对ＰＶＣ／ＳＢＲ的共混比、增容剂、增塑剂用量做了优化选择。同时对动态硫化ＰＶＣ／ＳＢＲ的硫化体系、硫化工艺条件进行了探讨,并比较了动态硫化对共混体性能的影响。结果表明：ＰＶＣ／ＳＢＲ为８０／２０,增容剂ＡＢＳ／ＳＢＲ－ＭＡ为５／５时,选用半有效硫化体系,１６５℃下动态硫化６ｍｉｎ,共混物综合性能最佳     

低密度聚乙烯接枝烯基双酚A醚对HDPE／PC共混体系性能的影响

本文采用烯基双酚Ａ醚接枝低密度聚乙烯（ＬＤＰＥ－ｇ－ＤＢＡＥ）作为高密度聚乙烯／聚碳酸酯（ＨＤＰＥ／ＰＣ）共混体系的增容剂,初步研究了ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系性能的影响。通过对共混物形态观察、耐热性能及力学性能测试,发现ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系有良好的增容效果;并发现了增容剂的最佳用量质量比大致为１０％,提高增容剂的接枝率更有利于改善共混物的性能。６５／３５ＨＤＰＥ／ＰＣ共混物的ＨＤＴ为９２℃,拉伸强度３０２ＭＰａ,冲击强度２９８ｋＪ／ｍ２,分别比未加增容剂时的８２℃,２７３ＭＰａ和１５５ｋＪ／ｍ２有较大提高。     

增容剂对HDPE／AS合金流变和力学性能的影响

研究了增容剂氯化聚乙烯接枝（丙烯腈／苯乙烯）共聚物对ＨＤＰＥ／ＡＳ共混体系加工流变性能和力学性能的影响。增容剂使共混体系的塑化时间减少,且随着增容剂用量的增加,共混体系的平衡扭矩和拉伸强度增大,而断裂伸长率在ＨＤＰＥ／ＡＳ／ＰＥ－Ｃ－ｇ－ＡＳ＝８０／２０／４时出现极大值;螺杆转速的增加使共混体系的平衡扭矩增大。     

原位增容HDPE／PET共混体系反应挤出形态结构的研究

通过扫描电镜照片（ＳＥＭ）研究了ＨＤＰＥ／ＰＥＴ共混体系在双螺杆反应挤出过程中,共混合金冲击断面的形态特征。结果表明,增容剂ＥＶＡ或ＥＡＡ均对ＨＤＰＥ／ＰＥＴ共混体系具有一定的增容作用;使分散相颗粒减小,且变得较为均匀,两相界面变得模糊,界面粘结力增强。其中,ＥＡＡ的增容效果优于ＥＶＡ。在此增容的基础上,选用有机化合物Ｄ作为催化剂,在熔融加工的过程中,使ＰＥＴ与ＥＶＡ或ＥＡＡ发生酯交换或酸－酯交换反应,生成ＰＥＴ－ＥＶＡ或ＰＥＴ－ＥＡＡ接枝共聚物,达到了原位增容ＨＤＰＥ／ＰＥＴ共混体系的目的,从而进一步改善了体系的相容性,共混体系的力学性能也得到了有效的提高     

马来酸酐接枝SBR增容改性PVC／SBR共混体的研究

采用化学接枝法和力化学接枝法制得马来酸酐（ＭＡＨ）接枝ＳＢＲ（ＳＢＲ－ＭＡＨ）作为ＰＶＣ／ＳＢＲ共混物的增容剂,并对不同方式的接枝物的增容效果进行了对比。     

Toughness and morphology of radiation‐crosslinked natural rubber modified polystyrene

γ‐Radiation vulcanized natural rubber (RVNR)/phase transfer/suspension polymerization technique was used to prepare high‐impact polystyrene (HIPS) in bead form. The high notched Izod impact resistance of HIPS based on RVNR was observed and compared with that of unmodified PS. The impact resistance of HIPS based on RVNR was further enhanced by addition of 10% of polystyrene‐block‐polyisoprene‐block‐polystyrene copolymer. A mesh structure of all crosslinked rubber particles containing polystyrene and long crazes in HIPS were observed under electron microscopy. Copyright © 2003 Society of Chemical Industry     

Rubber toughening of polystyrene through reactive blending

Acrylonitrile-butadiene rubber having carboxylic acid groups (XNBR) and polystyrene having oxazoline groups, were melt blended in a Rheomix mixer under optimized conditions, The ratio of rubber to polystyrene phase was kept constant at 1:4 by weight. The concentration of the reactive oxazoline groups in the polystyrene phase was varied by mixing polystyrene (PS) with a copolymer of styrene and vinyl oxazoline (OPS). A torque rise observed during blending was found to be related to the concentration of oxazoline-carboxylic acid pairs. This torque rise, and independently measured increases in viscosity, both indicate inter-polymer crosslinkihg. Scanning electron microscopy was used to observe the morphology of the blends. Improved rubber phase dispersion was observed with increasing oxazoline concentration. Instrumented impact strength measurements were made using an unnotched Charpy technique. The plastic yielding was then quantified with the use of a ductility ratio. The impact strengths and ductility of the reactive blends are found to be up to 73% greater than those of the corresponding non-reactive blends. Increasing the OPS concentration beyond 5% results in decreasing impact strength, for as the compatibility increases, the rubber particle size decreases below an effective size for rubber toughening. Similar impact improvement is observed when the major PS phase is substituted with high impact polystyrene (HIPS) containing some OPS.     

Glassy polymer solutions: some morphology—property relationships

The in-situ crystallization of low molecular weight crystalline organic compounds in general purpose and high impact polystyrene has been studied. Three modes of crystallization, namely needle-like, dendritic and tiny crystalline particles have been observed in these systems. Phase diagrams of tetrachloroxylene and tetrachlorobenzene with high impact polystyrene have been constructed. The effects of the crystalline additive, its concentration and morphology on some mechanical properties have been analysed. A significant difference between general purpose and high impact polystyrene was observed regarding their mechanical behaviour in the presence of the crystalline additives. Exudation and crystallization of the crystalline additives on the surface are also discussed. It is shown that these phenomena can be enhanced by annealing and stress crazing.     

Super HIPS: improved high impact polystyrene with two sources of rubber particles

Significant improvements in impact strength were achieved in polystyrene blends that combined conventional HIPS particles in combination with particles produced by compositional quenching. A commercial HIPS was solvated and blended with additional polystyrene, rubber and diblock copolymer, and the mixture was flash devolatilized to give the end-product. Impact strengths of injection and compression molded samples and tensile properties are reported. It is known that the best impact modified polystyrene obtained by compositional quenching, here called aHIPS, has smaller and lower modulus rubber particles than conventional HIPS, and has more than twice the impact strength of conventional HIPS. The novel blends of HIPS and aHIPS reported here exhibit synergism, the impact strength of the blend being higher than expected as a linear average of the component properties. The rubber phase volume including occlusion was held at 23%. An interior optimum in rubber efficiency (i.e. Izod impact per unit weight of rubber) was observed when 75% of the phase volume was derived from HIPS while an interior minimum was observed when 25% of the phase volume was derived from HIPS. The elongation at break and tensile impact strength exhibited a form of negative synergism, indicating that conventional HIPS is superior in low speed tests and aHIPS is better in high speed tests such as Izod.     

Photochemical aging and processability of life‐time‐controlled polystyrene/high‐impact polystyrene blends

This work investigated the influence of the addition of acetophenone and benzophenone (2.5 and 5%) on the photodegradability of polystyrene/high‐impact polystyrene blends (50/50 w/w) prepared by sheet extrusion, aiming to improve their decomposition during exposure to a natural environment. The modified materials were submitted to photodegradation under controlled conditions, and the extent of degradation was monitored by suitable characterization techniques, such as infrared and ultraviolet–visible spectroscopy, viscosimetry, and measurements of the mechanical properties. The processability of the modified blends was also studied by capillary and oscillatory rheometry. Evidence for the formation of hydroperoxides and carbonyl groups, the occurrence of chain scission, and the loss of mechanical properties was achieved, being greater for samples with benzophenone. It was also observed that for the same ketone level, benzophenone caused greater changes in the mechanical properties, and this was in agreement with the decrease in the molecular weight observed. Thus, the addition of this type of chemical compound could enhance the photodegradability of polystyrene/high‐impact polystyrene blends without a significant effect on their processability and mechanical performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Castor oil based interpenetrating polymer networks,IV. Mechanical behavior

The physical and mechanical properties of interpenetrating polymer networks (IPN's) based on castor oil-urethane and polystyrene are detailed in this paper. Dynamic mechanical spectroscopy showed extensive but incomplete molecular mixing of the two polymers. The glass transition temperatures of the IPN's gradually merged from two distinct transitions into one broad transition at an intermediate temperature as the crosslink level of the castor oil component was increased. At low polystyrene contents, the IPN's yielded stress-strain behavior similar to reinforced elastomers, but at high polystyrene contents, they exhibited increased elongation. For example, the latter materials showed well developed yield points. Stress whitening and necking were also observed, suggesting a possible failure mechanism by crazing. Cold drawing was exhibited by the materials under tension. The tensile strength and Young's modules were enhanced as the polymer II (polystyrene) content was increased at constant crosslink level of polymer I (castor oil-urethane). A similar effect was also observed by maintaining the polystyrene content constant but increasing the crosslink level of polymer I. The impact strength of the materials ranged from 32.1 to 53.4 N · m/m, which is approximately two to three times that of homopolymer polystyrene. The best materials were those with compositions in the range of 40-46 percent castor oil-urethane. The materials prepared by using tolylene diisocyanate as crosslinker for the castor oil phase had the best impact properties, especially at an NCO/OH ratio of 0.95.     

Mechanism of reinforcement in rubber-modified polystyrene systems studied by use of a miniature dart drop test

A miniature dart drop test was used in a study of the mechanism of reinforcement in impact resistant rubber-modified polystyrene. A typical SBR-polystyrene system was diluted with varying amounts of polystyrene, and thin compression moldings were made from each blend. The impact-whitened areas were observed directly under the microscope and photomicrographs are presented. The whitening is caused by scattering of light from interfacial separation of portions of many rubber particles from polystyrene and by formation of a multitude of microcracks and/or crazes, starting at the partially separated particles. The absorption of energy by this mechanism can be very large. The driving force for the initial separation appears to be the triaxial tension under which the rubber particles exist, and this results from the higher volume shrinkage rate of rubber compared to that of polystyrene. Included also are photomicrographs taken of specimens after tensile stretching, and the mechanism derived from the impact case is extended to explain the increased elongation and corresponding whitening.     

Rheological and mechanical properties of compatibilized polystyrene/ethylene vinyl acetate blends

In this study, a blend of polystyrene (PS)/ethylene vinyl acetate (EVA) (PS/EVA, 90 : 10 wt %) was compatibilized with three different block copolymers, in which their end blocks were compatible with either styrene or EVA. The compatibilized blends with different compositions were prepared using a twin‐screw extruder and injection molded into the required test specimens. Mechanical properties of the blends, such as tensile properties and Charpy impact strength, morphology of tensile fractured surfaces, rheological properties, and thermal properties, were investigated. The results show that the interaction between the dispersed and continuous phase can be improved by the addition of a compatibilizer. Appreciable improvement in the impact strength of the blend with 15 wt % of compatibilizer C (polystyrene‐block‐polybutadiene) was observed. Its mechanical properties are comparable to those of the commercial high‐impact polystyrene, STYRON 470. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2071–2082, 2004     

Simultaneous interpenetrating networks based on castor oil elastomers and polystyrene. V. Behavioral trends and analysis

The morphology and/or mechanical properties of simultaneous interpenetrating networks, SINs, based on castor oil elastomers and crosslinked polystyrene, were studied by electron microscopy, stress–strain analysis, and/or Izod impact tests. Several synthetic details were changed systematically and the concomitant changes in morphology or particular properties observed. The toughness of elastomer SINs increased with decreasing domain size of the polystyrene dispersed phase. The use of a prepolymer for the elastomer network synthesis promotes the formation of larger polystyrene domains. The impact resistance of the SINs increased with the total elastomer content. Properly crosslinked and postcured compositions developed impact energies of about 60–70 J/m. SINs based on castor oil-derived elastomers and crosslinked polystyrenes form prototype engineering materials which already compared satisfactorily to commercial polymers in terms of mechanical behavior.     

Ultrasonic degradation of the gel phase in impact polystyrenes

The rupture of the crosslinked rubber membranes in the gel particles of impact polystyrene by ultrasonic energy has been discovered to be a novel route for the semiquantitative analysis of the grafted and occluded polystyrene of the composite. Applying this new technique, the weight-average molecular weight of the matrix, grafted, and occluded polystyrene of a bulk-polymerized impact polystyrene was found to be approximately the same.