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医用CPE力学性能的研究 总被引:2,自引:0,他引:2
本文以搅拌式固法对HDPE进行氯化,探讨了CPE的氯含量,氯化温度及不同改性手段对材料力学性能的影响。实验结果表明,材料结晶区和无定型区,表面和内部的氯化程度因氯化温度、氯化速度的不同而有差异,当氯化温度低于HDPE熔点时,氯化反应仅发生在无定型区,当氯化温度高于HDPE熔点时,产品具有均匀的氯分布,高温氯化将使氯化速度增大,通过氯化温度和速度的调节,可在氯含量相同时,得到性能明显不同的产品。 相似文献
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在125~135℃下氯化所得低度氯化聚乙烯(LCPE)的结晶度和熔点随其氯含量增加迅速下降;在80℃氯化所得LCPE的结晶度随其氯含量增加稍有降低,而其熔点基本不变;当氯化温度远低于原料HDPE的熔点时,局部过热是引起低熔点晶粒破坏、产物结晶度降低的主要原因。 相似文献
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以酶解木质素为原料,在水相条件下通入氯气合成氯化木质素。考察了木质素与水的配比、有无紫外光催化、反应温度和通氯量对产物得率和氯含量的影响,并对产物进行了红外光谱和热重分析。结果表明,在氯气过量的情况下,产物氯含量达到29.8%,有紫外光催化时产物氯含量比较低,不加热时的产物氯含量更高,产物氯含量随氯气的增加而增大。氯化木质素的红外光谱图在1720cm-1处羰基强度明显增强,680cm-1附近出现C-Cl的特征吸收峰,说明Cl2与酶解木质素发生了取代反应。热重分析结果表明,氯化木质素的耐热性比酶解木质素稍差。与PVC共混改性的结果表明,氯化木质素改善了原有木质素分子的极性,有望作为极性高聚物共混改性的相容剂使用。 相似文献
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前言近年来,氯化聚乙烯(CPE)得到迅速发展,它不仅作为PVC的增韧改性剂,且具有塑料和橡胶的双重性能.以CPE为基础的橡胶,抗张强度、抗撕强度,耐臭氧等方面与氯丁橡胶相似;耐磨耗、介电性能、耐热老化、耐汽油等方面优于氯丁橡胶,是一种很有价值的新材料.CPE因含氯量和氯化条件不同而型态各异,可以是塑料、弹性体或刚性树脂.一般来说,溶液法制得的CPE性能主要决定于氯含量,而悬浮法和固相法CPE的性能除了氯含量以外,氯化温度等有极大的影 相似文献
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利用等离子体处理技术对PE-WPC进行表面处理以改善其胶接性能,将处理后的木塑复合材料分别贮存在真空(室温)、空气(室温)和空气(低温)环境中,利用XPS分析手段,研究了等离子体处理PE-WPC表面元素的变化,以此表征贮存环境对等离子体处理表面时效性的影响。结果表明,随着放置时间的延长,贮存于真空、空气(室温)和低温环境中的等离子体处理PE-WPC表面的C元素相对含量均增加,O元素则相反,O/C值降低。与空气(室温)环境相比,真空和低温环境下等离子体处理PE-WPC表面O/C值降低的幅度减缓。 相似文献
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Rui Shi Quanyong Liu Tao Ding Yanming Han Liqun Zhang Dafu Chen Wei Tian 《应用聚合物科学杂志》2007,103(1):574-586
In this study, a soft and thermoplastic starch with an improved ageing‐resistant property was prepared by melt blending method for a biodegradable biomaterial. The glycerol content varies from 30 to 60 wt %. The aging temperature and humidity of the glycerol‐plasticized thermoplastic starch (GTPS) was 37°C and 50 ± 5 RH %, respectively. The retrogradation was characterized by X‐ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), Fourier transform infrared (FTIR), and the stress‐strain mechanical properties. The XRD results suggest that high content of glycerol promotes the formation of single helix structure of V‐type, but inhibits double helix structure of B‐type. Changing of the tan δ, storage modules (E′), and the glass transition temperatures as a function of glycerol content and ageing time was detected by DMTA. FTIR result shows that the shifting speed of the peak of hydroxyl group stretching fell as the glycerol content increased. The glycerol content has no obvious effect on the mechanical properties when it is high enough. Results from all characterizations demonstrate that the ageing speed is closely relative to the plasticizers content. The higher content of glycerol possesses an obviously inhibitory effect on the ageing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 574–586, 2007 相似文献
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Michael G. Huson 《Polymer International》1991,26(3):157-161
Wool can be deaged both thermally and aqueously, resulting in disruption of the network of secondary bonds. The ensuing increase in mobility of the macromolecular chains manifests itself as a decrease in the glass transition temperature; hence this property can be used to monitor the ageing/deageing process. The extent and stability of the network that forms on ageing is a function of the temperature and time of formation. If samples are allowed to age for two consecutive periods of time at different temperatures then two independent networks are formed, each with its own characteristic glass transition temperature. The moisture content, thermal history and scan rate must be carefully controlled during any thermal analysis. It has also been shown that deageing can be used to facilitate the temporary setting of wool. 相似文献
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