共查询到20条相似文献,搜索用时 281 毫秒
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以过氧化二异丙苯(DCP)为引发剂,甲基丙烯酸缩水甘油酯(GMA)为活性单体,高抗冲苯乙烯(HIPS)通过熔融接枝制得了动能化的高抗冲聚苯乙烯接枝物(HIPS-g-GMA)。用红外光谱和电子能谱对其结构进行了表征。HIPS-g-GMA的红外谱图,证明GMA已经接枝到HIPS上。电子能谱分析也提供了相似的结论。研究了单体浓度和DCP用量对产物接枝率的影响,并用化学滴定方法测定了接枝物的接枝率。用DSC、SEM、WAXD、DMA等研究了PBT/HIPS和PBT、HIPS-g-GMA的结晶、形态结构、动态力学性能及力学性能随组成的变化。SEM及DMA分析表明增容后体系的相容性得到改善,力学性能有较大提高。 相似文献
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氧化钕填充聚丙烯的等温结晶动力学研究 总被引:4,自引:2,他引:4
用DSC法研究了氧化钕微粉填充聚丙烯的等温结晶动力学.结果表明,加入少量氧化钕可明显提高聚丙烯的基体结晶速率和结晶度,降低球晶径向生长的单位面积表面自由能;从Avrami和Hoffman理论出发都可得出稀土氧化物Nd2O3填充聚丙烯后可明显改变聚丙烯的结晶行为. 相似文献
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利用DSC和偏光显微镜等手段研究了部分成核剂对聚丙烯均聚物(PP)、低乙烯含量聚丙烯共聚物及聚丙烯/聚乙烯(PP/PE)共混物结晶行为的影响,结果表明所用成核剂对PP和改性PP具有一定的普适性。聚丙烯共聚物中,由于链结构规整性变差,成核剂的作用显得特别突出,而PP/PE共混物中,由于成核剂向PE相迁移而使其对PP结晶的成核效率降低。 相似文献
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《理化检验(化学分册)》2017,(9)
正六溴环十二烷(HBCDD)是一种高溴含量的脂环族添加型阻燃剂,因其具有用量少、阻燃效果好、对材料物理性能影响小等特点,大量用于建筑物和汽车中经处理的聚苯乙烯保温板、高抗冲聚苯乙烯电气和电子设备,也用于聚丙烯、苯乙烯树脂、涤纶织物和合成橡胶涂层等,现已成为世界上仅次于十溴二苯醚和四溴双酚A的第三大用量的阻燃剂。但研究发现HBCDD对生物体具有持久性、蓄积性 相似文献
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抗冲共聚聚丙烯结构研究进展 总被引:1,自引:0,他引:1
综述了已广泛应用于汽车及家电行业的抗冲共聚聚丙烯结构的研究进展,重点介绍了抗冲共聚聚丙烯组成、链结构及聚集态结构的研究方法及研究进展。阐述了典型抗冲共聚聚丙烯的组成、链结构及聚集态结构,总结了研究抗冲共聚物组成、链结构以及聚集态结构的研究方法。同时还回顾了聚合工艺条件对抗冲共聚聚丙烯的组成及链结构的影响规律以及组成及链结构对材料聚集态相结构的影响规律。最后重点回顾了异质多相体系的组成、链结构及聚集态相结构与性能之间的关系,展望了抗冲共聚聚丙烯领域的某些可能发展方向。 相似文献
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聚酯型聚氨酯样品用基体辅助激光裂解离子化质谱(MALDI-TOF/MS)和热裂解色谱质谱(PYGC/MS)方法进行了鉴定,PYGC/MS方法可检出PU的一些组成单元的化学结构,但PYGC/MS中大多数的峰,无法从常规的标准化合物的质谱数据库中检索到,而MALDI-MS方法,可明确测出PU试样各种单元的组合、聚合度及PU长链的序列分布,质量数范围可达2300。 相似文献
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Li Qiu Wang Qing Shan Li Hui Peng Ma Xiao Feng Guo Rui Hong Wang Gang Yao 《中国化学快报》2009,20(4):483-486
Polypropylene synthetic paper releasing anion was prepared from polypropylene resin,anion additives,titanium dioxide,etc.,by calendar forming method.The synthetic paper was tested by anion detector,SEM,AFM,etc.Tensile strength,elongation at break, right angle tear strength of the polypropylene synthetic paper reached the GB 13022 or QB/T1130 Standard.The synthetic paper was water and oil resistance,and released anions 10,530 cm~(-3).It was environment-friendly,and a kind of good material for human's heal... 相似文献
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Polypropylene synthetic paper releasing anion was prepared from polypropylene resin,anion additives,titanium dioxide,etc.,by calendar forming method.The synthetic paper was tested by anion detector,SEM,AFM,etc.Tensile strength,elongation at break,right angle tear strength of the polypropylene synthetic paper reached the GB 13022 or QB,1r/T130 Standard.The synthetic paper was water and oil resistance.and released anions 10,530 cm-3.It Was environment-fendy.and a kind of good material for human'S health. 相似文献
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高分子材料的组成、 组分分布及链结构与宏观性能紧密相关. 因此, 分析多组分釜内合金材料的链结构特点与性能之间的关系至关重要. 采用升温淋洗分级的方法对两种采用序贯两段聚合原位合成的等规聚丙烯/聚丁烯-1(iPP/iPB)釜内合金在-30 ℃~140 ℃温度范围进行分级, 采用核磁共振波谱仪、 傅里叶变换红外光谱仪、 差示扫描量热仪和凝胶渗透色谱仪等表征了级分的链结构及序列分布、 热行为、 分子量(Mw)及分子量分布(Mw/Mn)等. 结果表明iPP/iPB合金主要由5种级分组成, 高等规聚丁烯(iPB)为主要组分, 同时含有少量的丁烯-丙烯嵌段共聚物(PB-b-PP)和等规聚丙烯(iPP)等. 随淋洗温度升高, PB-b-PP级分中PP嵌段长度逐渐增加, PB嵌段长度逐渐减小; 在相同的淋洗温度, 合金B的嵌段共聚物级分中PP嵌段较长且结晶较完善; 合金B中iPB组分及嵌段共聚物组分含量较高, 使得合金B具有较高的拉伸强度、 弯曲强度、 优异的抗冲击性能、 较高的维卡软化温度及较快的晶型转变速率. 相似文献
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J. L. Kardos A. W. Christiansen Eric Baer 《Journal of Polymer Science.Polymer Physics》1966,4(5):777-788
The structure of polypropylene crystallized at pressures up to 5000 atm. has been studied. Upon slow cooling from the melt at 320 atm., the γ modification, previously found only in low molecular weight and stereoblock fractions, begins to appear in small amounts in addition to the normal α monoclinic form. As the pressure is increased further, a larger proportion of the sample crystallizes in the γ form until, at 5000 atm., only the γ modification is present. X-ray and DTA studies show that the γ form of polypropylene transforms to the normal α modification at a temperature only slightly below the γ melting point. Evidence is presented which favors the occurrence of a solid-state transition as a model of transformation to the α form. Results from isothermal crystallizations at low supercoolings and annealing experiments under high pressure show that the melting point of the γ modification of polypropylene is very sensitive to crystallite perfection. 相似文献
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Ozonisation of polypropylene in bulk causes chain scission through autooxidation processes at room temperature and produces mainly α-ω diketone polypropylene sequences. With poly(vinylchloride) or polyethylene, formation of α-ω diacid sequences has been observed. Hydroperoxides parallel ketone formation but they are grafted onto the polymer backbone. They may be used to initiate the polymerisation of vinyl monomers during the processing of the polypropylene. 相似文献
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John C. Chadwick 《Macromolecular Symposia》2001,173(1):21-36
The fundamental factors determining the performance of state‐of‐the‐art MgCl2‐supported catalysts for polypropylene are becoming increasingly evident. Polymer yield, isotacticity, molecular weight and molecular weight distribution are dependent on the regio‐ and stereoselectivity of the active species. Chain transfer with hydrogen after the occasional regioirregular (2,1‐) insertion has a strong effect on molecular weight and is the main reason for the high hydrogen response shown by high‐activity catalysts containing diether donors. Hydrogen response is also dependent on stereoselectivity. The probability of a stereo‐ or regioirregular insertion can be related to the lability of donor coordination in the vicinity of the active species. Results with different catalyst systems can be interpreted on the basis of a propagation model involving interconverting active species, such that polypropylene produced using MgCl2‐supported catalysts can be regarded as a stereoblock polymer comprising (highly) isotactic sequences, moderately isotactic (isotactoid) sequences and syndiotactoid sequences. Strongly coordinating donors will give stereoregular polymers in which highly isotactic sequences predominate. 相似文献
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Mélanie AubertCarl-Eric Wilén Rudolf PfaendnerSimon Kniesel Holger HoppeMichael Roth 《Polymer Degradation and Stability》2011,96(3):328-333
In this work, we report the synthesis and use of an innovative multifunctional radical generator, i.e., bis(1-propyloxy-2,2,6,6-tetramethylpiperidyl)-4-diazene (AZONOR) that alone can effectively provide flame retardancy and self-extinguishing properties to both polypropylene films and plaques. Polypropylene samples containing very low concentrations of 0.25-1 wt% of this additive can successfully pass not only the fire standard tests of DIN 4102 B2 and NF P92-505 but also the more challenging UL94 VTM-2 standard. Besides relative low levels of addition and having no detrimental effect on polypropylene appearance or its mechanical and processing properties another great advantage offered by this flame retardant is its multifunctionality, i.e., high flame retardant durability after artificial weathering. Thus, even after 2000 h of artificial weathering no significant decrease in flame retardant efficacy could be observed. 相似文献
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The structure and properties of a polypropylene microporous film prepared by biaxial stretching of non-porous polypropylene film of high β-crystal content were investigated. The porosity of these films can be as high as 30–40%, and the average pore size was around 0.05 μm. The films were found to have the structure of a two-phase interpenetrating network; both the polypropylene and the pore regions were three-dimensionally continuous. The advantages of the biaxially stretched microporous films are the combination of high permeability to fluids with good mechanical properties and almost circular pore shape with narrow pore size distribution. The application of this microporous film for battery separators, filtration membranes and substrates of functional polymer composites is discussed. 相似文献
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