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概述了国内外特种PVC树脂的发展状况,详述了国内特种PVC树脂发展滞后的原因,明确了我国特种PVC树脂发展的广阔前景,重点介绍了一种新开发的高抗冲PVC复合树脂。该特种PVC树脂的常温与低温缺口冲击强度高,耐候性尤为突出,可广泛应用于汽车工业、工程塑料、电器仪表、高品质特种管道及其他高品质化学建材等行业。 相似文献
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本文介绍了八十年代以来国内外硬PVC管材的消费情况,叙述了硬管用PVC树脂品种牌号及主要性能指标。简述了美国两大公司开发的一种硬管用新型树脂一PVC球形树脂的研究情况。PVC球形树脂具有独特的优异性能,可大幅度提高管材加工过程中挤出速率。对扩大PVC球形树脂生产及应用有深远意义。 相似文献
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一、前言 采用不同的PVC树脂和添加剂设计不同配方,可以获得各种不同用途的PVC塑料。因此研究新型的PVC树脂添加剂、开发新的PVC塑料配方是发展聚氯乙烯工业的重要途径。 Brabender转矩流变仪为此提供了极大的便利。它作为PVC树脂、添加剂及加工条件的实验仪器已被PVC树脂及添加剂的生产者、塑料加工机械制造者和配方研究人员所广泛应用。 相似文献
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介绍了PVC糊树脂国内主要生产工艺,分析了我国PVC糊树脂的市场现状及前景,指出我国PVC糊树脂产能将在2013年达到饱和,氯碱企业应谨慎建设PVC糊树脂低端产品项目,加快PVC糊状树脂高端专用料的开发与建设。 相似文献
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Environmental stress cracking (ESC) (failure caused by crack and craze formation at a stress less than the yield stress) reduces the service life of many plastic products. This paper is concerned with ESC of rigid PVC products which are in contact with a plasticized PVC material. The ESC affect (as measured by elongation to break) is reduced at faster strain rates and by higher plasticizer viscosity, which suggests a mechanism requiring flow of plasticizer into a growing craze. Well fused (gelled) PVC made at a higher melt temperature slowed but did not eliminate environmental stress cracking. Rubber impact modifier added to the rigid PVC had no effect on ESC. Environmental stress cracking can be avoided by using flexible PVC that has a non-migrating plasticizer or by designing the product so that rigid PVC is not stressed while in contact with plasticized PVC. 相似文献
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世界PVC市场发展态势分析 总被引:1,自引:0,他引:1
分析了国外PVC市场发展态势以及国外PVC替代品动向,重点介绍了中国PVC市场发展态势、PVC产品应用与消费及PVC制品业存在的问题。 相似文献
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Poly(vinyl chloride) PVC pyrolysis and hydrolysis are conducted in a fixed bed reactor and in an autoclave, respectively, under different operating conditions such as the temperature and time. The product distribution is studied. For the PVC pyrolysis process, the main gas product is HCl (55% at 340°C), there is 9% hydrocarbon gas (C1–C5), the liquid product fraction is about 5% (at 340°C), and the solid residue fraction is about 31% (at 340°C). For the hydrolysis process, the main gas product is HCl (55.8% at 240°C) and the solid residue is about 49.6% (at 240°C). The pyrolysis liquid product is analyzed by using gas chromatography with magic‐angle spinning. Aromatic hydrocarbons are the main class (90%), of which the major part is benzene (33%). The residue produced through pyrolysis and hydrolysis is investigated by high‐resolution solid‐state 13C‐NMR. These details revealed by the high‐field NMR spectra provide importmant information about the chemical changes in the PVC pyrolysis and hydrolysis process. The mechanism of PVC hydrolysis dechlorination is also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3252–3259, 2003 相似文献
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The degradation of polyethylene terephthalate (PET) waste by making use of hydrazine monohydrate was investigated at ambient temperature and pressure. The aminolysed end products obtained were characterized with chemical tests and spectroscopic techniques namely IR, UV‐visible spectroscopy and NMR, and the differential scanning calorimeter (DSC). The end product was characterized as terephthalic dihydrazide (TPD) and further used in PVC compounding as secondary plasticizer. The hardness, tensile strength, elongation at break, thermal stability, and compatibility of the PVC sheet were studied and concluded that the aminolysed product may find potential application as secondary plasticizer in PVC formulations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Ivo Mersiowsky 《乙烯基与添加剂工艺杂志》2002,8(1):36-44
End-of-life PVC products are predominantly disposed of with construction waste or with municipal solid waste in sanitary landfills. This waste management option is currently subject to debate because of environmental issues. A material and substance flow analysis was conducted to estimate the quantitative relevance of PVC products and their constituents in municipal solid waste. Landfill simulation assays demonstrated the long-term behavior of PVC products and the fate of additives under landfill conditions. The PVC polymer was found to be stable. A loss of plasticizers may occur in case of insufficient compatibility with the PVC compound coupled with microbial consumption at the PVC product surface. Losses of stabilizers are generally restricted to transient leaching from the product surface. Plasticized products show a somewhat stronger inclination to release their stabilizers. The findings indicated that additional measures specifically directed at post-consumer PVC waste in landfills are not necessary. 相似文献
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聚氯乙烯回收利用与环境问题的进展 总被引:5,自引:1,他引:4
总结了当前PVC的回收利用及其对环境影响的研究进展,并对PVC未来的应用及其回收利用进行了一些思考。文章指出,在发展PVC的同时,仍然必须充分估计PVC的潜在问题,尽量将PVC用作长寿命的产品,产品的设计必须考虑便于日后回收利用,并加紧PVC回收利用的产业化研究。 相似文献
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《塑料、橡胶和复合材料》2013,42(4):152-156
AbstractThe degree of gelation reached upon processing influences heavily the properties of poly(vinyl chloride) (PVC) made parts. Gelation involves the conversion of the initial PVC particle structure into an increasingly homogeneous melt and therefore the rheological properties of PVC at low temperatures are very different from those at higher ones. Whereas the former involves both wall slip and particle flow, the latter yields a more conventional behaviour.As a consequence, the nature and origins of the different mechanisms giving rise to wall slip in PVC compounds must be taken into account when trying to understand the relationship(s) between the processing conditions, the physics of the gelation mechanism, and the final product characteristics.This work involves the study of the rheological properties of PVC compounds for different initial gelation levels and the identification of wall slip mechanisms using rotational rheometry. 相似文献
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采用气相色谱-质谱法并结合热重分析法对聚氯乙烯(PVC)的热裂解行为进行了研究。首先对PVC的热失重行为进行考察,确定最佳裂解温度;然后分别在350℃和600℃下对PVC进行热裂解,并用气相色谱-质谱联用仪对裂解产物进行定性和半定量分析。结果表明:在350℃下,PVC裂解产物主要以HCl和苯等易挥发物质为主;在600℃下,裂解产物为多环芳烃,但未检测到HCl。根据裂解产物的种类及相对含量的变化,确定PVC的分段裂解回收工艺,从而提高了热裂解产物的回收率和热裂解效率。 相似文献
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It is well known that during aging or annealing, materials become stiffer and more brittle, and creep and stress relaxation rates decrease. Research in this area is very important because physical aging (annealing) plays a large role in the production of products, and it also occurs during the use of the objects or products. The decrease of free volume with time is unavoidable even at ambient temperatures. The influence of fusion and physical aging on the toughness of extruded PVC profiles was investigated. It is known that the toughness of PVC is influenced by secondary crystallization—after primary particles of PVC are partially melted. Recrystallization upon cooling or annealing forms a three-dimensional structure tying together the primary particles. This three-dimensional structure normally produces a tougher PVC product. The density of glassy PVC can be changed by changing the quenching rate. The density can be further changed by annealing below Tg. The densification of a glassy polymer normally leads to a less tough PVC product. This study uses density measurements and differential scanning calorimetry scans to measure the amount of enthalpy relaxation (related to densification) and crystalline melting energy (related to the amount of crystallinity) for various annealed samples. These are related to toughness as measured by notched Izod and droppeddart impact tests. 相似文献
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To improve the mechanical properties of poly(vinyl chloride) (PVC), the possibility of combining PVC with elastomers was considered. Modification of natural rubber (NR) by graft copolymerization with methyl methacrylate (MMA) and styrene (St) was carried out by emulsion polymerization by using redox initiator to provide an impact modifier for PVC. The impact resistance, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) of St and MMA grafted NR [NR‐g‐(St‐co‐MMA)]/PVC (graft copolymer product contents of 5, 10, and 15%) blends were investigated as a function of the amount of graft copolymer product. It was found that the impact strength of blends was increased with an increase of the graft copolymer product content. DMA studies showed that NR‐g‐(St‐co‐MMA) has partial compatibility with PVC. SEM confirmed a shift from brittle failure to ductility with an increase graft copolymer content in the blends. The mechanical properties showed that NR‐g‐(St‐co‐MMA) interacts well with PVC and can also be used as an impact modifier for PVC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1666–1672, 2004 相似文献