聚合物合金技术动向(下)

2.3 聚苯醚系聚合物合金 聚苯醚(改性PPO/PPE)系聚合物合金已从PS(聚苯乙烯)、HIPS(高抗冲聚苯乙烯)开始并扩大到与ABS、PA、聚烯烃、聚酯、热塑性弹性体、PPS等组成合金,用作工业的新材料。 PPE/PS系相容性聚合物合金,所显示的玻璃化温度有加成性,扩大了材料的应用范围。目前已应用于电气电子及其相关领域、OA机器、汽车部件、给排水部件、精密部件等,形成了相当大的市场。该类合金技术的特征有:应用PS、HIPS技术,控制PS分子     

一种新型EPDM改性聚苯乙烯高抗冲材料的制备

以聚苯乙烯(PS)为基体材料,以三元乙丙橡胶(EPDM)为增韧剂,以轻质CaCO_3为填充剂,对PS材料进行增韧改性;探讨了EPDM含量、轻质CaCO_3含量对改性PS塑料性能的综合影响。实验结果表明:当EPDM与PS的质量比为4∶6,并添加20%的轻质CaCO_3时,改性PS塑料的拉伸强度达18.1 MPa (17.0 MPa),抗冲击强度达187.2 J/m (92.0 J/m),熔融指数达2.6 g/10min (2.5 g/10min),满足推荐性国家标准GB/T 37198-2018的要求,且均大于当前市面几种常见牌号HIPS性能的最低值。所制得的改性PS材料可作为HIPS的替代产品,完全适用于塑料饰品的加工和生产。     

HIPS／改性氢氧化镁晶须复合材料的研究

采用乙烯基硅烷在氢氧化镁(MH)晶须表面引入乙烯基后与苯乙烯进行原位聚合,得到了聚苯乙烯改性的氢氧化镁晶须(MMH).将MMH与高抗冲聚苯乙烯(HIPS)熔融复合制备了HIPS/MMH复合材料,研究了复合材料的微观结构和力学性能.结果表明,聚苯乙烯包覆在MH表面,并形成了共价键结合;原位聚合改性改善了MH在HIPS基体中的分散性,增强了MH和HIPS的界面相互作用,显著提高了HIPS/MMH复合材料的拉伸强度与冲击韧性.     

橡胶含量及加工条件对HIPS/PS/PB-g-PS共混物性能的影响

用乳液聚合以CHP-FeSO4为引发体系合成PB-g-PS接枝粉料,与商业高抗冲聚苯乙烯(HIPS)和聚苯乙烯(PS)共混制备HIPS/PS/PB-g-PS舍金.当HIPS的质量分数为10%,PB-g-PS的加入量为15%时体系发生脆韧转变.当HIPS质量分数为10%,橡胶加入量为15%时,体系的冲击强度随挤出机转数的增加而变大.扫描电镜(SEM)研究表明:挤出机转数低加工时剪切强度不够,体系的相容性不好导致脆性断裂.     

苯乙烯类塑料耐老化性能研究

对纯聚苯乙烯(PS)、高抗冲聚苯乙烯(HIPS)、PS/(苯乙烯/丁二烯/苯乙烯)共聚物(SBS)共混物、添加助剂的PS和HIPS等5组试样进行紫外光加速老化。表征了5组试样老化前后的力学性能、特性粘度、分子链结构的变化。研究表明,紫外光加速老化使材料的力学性能降低,表层发生龟裂;表层的溶液粘度下降较明显,距厚度大于0.4mm时其粘度下降缓慢;傅立叶变换红外光谱谱图中在1720cm-1处出现明显的吸收峰,表明有CO生成;纯HIPS、添加助剂的HIPS和PS/SBS共混物在910、966cm-1处的吸收峰强度明显减弱,表明发生了烯烃碳碳双键的断裂,添加助剂的HIPS老化后的透过率保持率最高。     

在高抗冲聚苯乙烯装置上开发生产透明聚苯乙烯

介绍了在高抗冲聚苯乙烯(HIPS)装置上工业化试生产B-5型高性能透明聚苯乙烯(PS),研究了聚合条件、工艺等对PS性能的影响。结果表明,HIPS装置各个聚合釜的温度对B-5型PS性能的影响各不相同。加入丙烯酸甲酯共聚、提高单体转化率、加入3 L/h的白油可提高PS的冲击强度;当丙烯酸甲酯质量分数为7%时,PS的玻璃化转变温度(Tg)和维卡软化点(VST)分别为96℃和99.2℃,与美国陶氏化学公司685D透明PS(Tg为96℃,VST为100℃)大致相当。     

阴离子聚合法生产聚苯乙烯新技术

聚苯乙烯(PS)是通用树脂中的重要一员，包括通用聚苯乙烯(GPPS)、抗冲聚苯乙烯(HIPS)和可发性聚苯乙烯(EPS)。通常它是通过苯乙烯单体的游离基聚合反应制得的。生产GPPS和HIPS的装置一般采用连续本体聚合工艺，生产。EPS采用悬浮工艺。最近，国外一些公司开发出阴离子聚合生产聚苯乙烯的新技术，并有可能在近期实现工业化生产。     

2006年中国聚苯乙烯研发与应用论文题录

全程动态注塑对HIPS制品力学性能影响研究;纳米碳酸钙含量对PS发泡塑料泡孔形态的影响;天然胶乳包覆交联聚苯乙烯刚性粒子改性聚丙烯的研究;压缩条件下发泡聚苯乙烯蠕变本构关系及有限元分析;不同粒径氧化镁对ABS导热塑料热导率的影响.     

HIPS回收料的增韧改性研究

高抗冲聚苯乙烯(HIPS)是由弹性体改性聚苯乙烯制成的热塑性材料,HIPS是最便宜的工程塑料之一。而对于HIPS回收料来说,其性能相对于新料降低了很多,特别是冲击强度。本研究主要是通过添加SBS、蒙脱土、SMA对HIPS回收料进行增韧改性,同时采用多组对比的方法对HIPS回收料的性能进行比较,研制出综合性能达到甚至超越HIPS新料的HIPS回收料改性树脂。通过实验分析,当SBS添加8份,SMA添加3份,蒙脱土添加3份时其综合性能特别是冲击强度得到改善。     

集成橡胶增韧PS

应用集成橡胶[苯乙烯-异戊二烯-丁二烯橡胶(SIBR)]增韧聚苯乙烯(PS),当w(SIBR)为17.5% 时,所得高抗冲聚苯乙烯(HIPS)的冲击强度达380 J/m.与经典的PS增韧剂聚丁二烯橡胶、丁苯橡胶等相比,SIBR中包含异戊二烯成分.研究结果表明,异戊二烯起到了一定的增韧作用.该HIPS的透射电子显微镜照片显示,产品中没有经典的"海-岛"结构,而是出现了一种新的网络结构.     

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     

增韧阻燃高抗冲聚苯乙烯的研制

采用接枝(乙烯/丙烯/二烯)共聚物(EPDM)、K胶、(苯乙烯/丁二烯/苯乙烯)共聚物(SBS)和粉末丁腈橡胶(NBR)为高分子材料增韧剂,十溴联苯醚和三氧化二锑为阻燃剂,高抗冲聚苯乙烯(HIPS)为基体树脂通过共混、挤出过程制得增韧阻燃HIPS复合材料。对该复合材料的力学性能、阻燃性能进行测试,分析了该复合材料的微观结构,并讨论了复合材料的增韧机理。结果表明,SBS比其它3种增韧剂的增韧作用明显,并有良好的阻燃效果。     

Poly1‐hexene: New impact modifier in HIPS technology

Poly1‐hexene was prepared using a conventional heterogeneous Ziegler–Natta catalyst and its stereoregularity was characterized using ¹³C‐NMR analysis. New kind of high impact polystyrene (HIPS) was prepared by radical polymerization of styrene in the presence of different amounts of synthesized poly1‐hexene (PH) as impact modifier (HIPS/PH) and compared with conventional high impact polystyrene with polybutadiene (HIPS/PB) as rubber phase. Scanning electron microscopy (SEM) revealed that the dispersion of poly1‐hexene in polystyrene matrix was more uniform compared with it in HIPS/PB. The impact strength of HIPS/PH was 29–79% and 80–289% higher than that in HIPS/PB and neat polystyrene, respectively. FTIR was used to confirm more durability of HIPS/PH samples toward ozonation. To study the effect of rubber type and amount on the T_gs of polystyrene, differential scanning calorimetry was employed. Results obtained from TGA demonstrated higher thermal stability of HIPS/PH sample in comparison with conventional HIPS/PB one. Our obtained results suggest new high impact polystyrene that in all studied aspects has better performance than the conventional HIPS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43882.     

Influence of small rubber particles on the environmental stress cracking of high impact polystyrene

This article exploits the influence of rubber particle size (RPS) and rubber crosslinking on environmental stress cracking resistance (ESCR) of high impact polystyrene (HIPS), with special interest on the influence of small rubber particles fraction. Three commercial HIPS of high ESCR were selected and four batches of HIPS were prepared in‐house, including samples based on high cis and very high viscosity polybutadiene (PB). Their morphologies were analyzed by low angle laser light scattering, optical microscopy, and transmission electron microscopy, and the samples were submitted to flexural ESCR tests with fatty agents. The ESCR to sunflower oil was found to increase with the reduction of the rubber particles fraction smaller than 1–2 micron. Results have also confirmed that an increase in RPS is the key parameter to promote ESCR, although there is limit for RPS to be effective on ESCR improvement. The reduction of small rubber particles fraction in HIPS was achieved by using a high cis PB, that promotes low grafting efficiency of polystyrene onto PB backbone because of the low content of 1,2 vinyl isomer. Besides the ESCR improvements, HIPS with high cis PB showed higher elastic modulus and impact resistance than HIPS containing medium cis PB, which is desired for thickness reduction in food packaging and refrigeration cabinets. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Indentification and characterisation of high impact polystyrenes. II. Impact index

The optical density of high impact polystyrene (HIPS) solution in carbon tetrachloride (0.5 %) at 320 mμ is found to be indicative of the improvement in impact resistance of the HIPS sample. The percentage grafting has been determined in the HIPS samples by solvent extraction method, and the dependency of impact resistance of the percentage grafting is compared with that of optical density and impact resistance. From the results it appears that the optical densities are as indicative as the percentage grafting, of the impact strength. For the ease of calculations the values of optical density are expressed as whole numbers and are referred as impact indices.     

Fracture behavior of high-impact polystyrene under an aggressive environment

The fracture behavior of three high-impact polystyrene (HIPS) materials has been investigated using constant load at 1/2 h interval tests of margarine-exposed compact tension fracture mechanics specimens. Scanning electron microscopy has also been done on the fracture surfaces to correlate the micromechanics of fracture to the fracture test results. The results indicate that the proposed tests provide a useful approach to study the environmental fracture resistance (EFR) of HIPS under the influence of an aggressive environment. It was found that the EFR of HIPS under margarine, with comparable rubber content, improves with decreasing rubber particle size and increasing molecular weight.     

Thermally stimulated oxidative degradation of high impact polystyrene with nitric acid

The practical application of high impact polystyrene (HIPS) depends on the resistance to aging in aggressive environments. The investigation of morphological, mechanical, and chemical properties was made on HIPS samples of various thickness. The property deterioration of HIPS caused by concentrated nitric acid and heat was studied. The diffusion through micropores formed visible cracks that finally led to the complete destruction into a powder. The rapid loss in mechanical properties was explained in terms of scission reaction of the graft polybutadiene (PB) with the homopolystyrene (PS) matrix. Comparative measurements of pure PS and PB under the same conditions were helpful in resolving parallel reactions that preferentially take place in PS and/or in PB sequences. It was established that higher degree of nitration caused by higher temperature results in increased insolubility owing to parallel crosslinking reactions. The nitric acid attack on HIPS caused scission reactions, which also led to the oxidative degradation, more pronounced in the PS phase in the soluble part of HIPS.     

抗氧剂GM对HIPS热氧稳定性能的影响

抗氧剂GM是一种新型双酚单丙烯酸酯类抗氧剂,在聚合物加工过程中有着优良的热稳定性能。本文测定了添加不同含量的抗氧剂1010和抗氧剂GM的高抗冲聚苯乙烯(HIPS)树脂的氧化诱导参数及其经热氧老化后的力学性能以及色差值AE,分析了抗氧剂1010和抗氧剂GM在抗热氧老化方面的性能差异。结果表明,相较于常见的多元受阻酚类抗氧剂1010,GM由于独特的双官能稳定机理,能够有效提高HIPS的氧化诱导时间,并能在HIPS长期热氧老化的过程中体现出同抗氧剂1010一样优异的热氧稳定性能和抗氧化着色性能。     

Water absorption and mechanical properties of PP/HIPS hybrid composites filled with wood flour

Water absorption and mechanical performance of the injection‐molded hybrid composites prepared from different ratios of two polymer blends (57 wt%), two compatibilizers (3 wt%), and two wood species (40 wt%) were investigated. The ratio of polypropylene and high‐impact polystyrene (HIPS) gradually increased in the blend (from 10 to 30 wt%). Styrene–ethylene–butylene–styreneblock copolymer and maleic anhydride‐grafted PP (MAPP) were used as compatibilizer (3 wt%). The shore D hardness of the PP/wood composites was improved by the incorporation of the HIPS. The HIPS/wood flour composites showed higher tensile modulus but lower tensile strength than the PP/wood composites. The water resistance of the PP/wood composites decreased with increasing HIPS content. POLYM. COMPOS., 38:863–869, 2017. © 2015 Society of Plastics Engineers