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以Al(i-Bu)3(简称Al)为助催化剂,采用含有内给电子体的负载钛催化剂(简称Ti)体系催化1-丁烯(Bt)本体聚合,合成了聚1-丁烯热塑性弹性体(PB-TPE),考察了Al/Ti(摩尔比)、聚合温度对转化率、产物全同结构含量和力学性能的影响,研究了产物的结晶行为和微观结构。结果表明,随着Al/Ti的增加,聚合产物的全同结构含量先升高后降低,当Ti/Bt(摩尔比)为3×10-5、Al/Ti为400时,全同结构质量分数可达到80%;随聚合温度的升高单体的转化率增大,在40℃时,转化率达86%,但全同结构含量明显降低。PB-TPE的玻璃化转变温度为-23.10℃,熔点为111.28℃,结晶度为29%。采用含内给电子体的Ti合成的PB-TPE的全同结构含量和结晶度较不含内给电子体的Ti合成的PB-TPE高,从而使其拉伸强度达14MPa。 相似文献
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以二苯基甲烷-4,4′-二异氰酸酯(MDI)、1,4-丁二醇(BDO)、聚己二酸-1,4-丁二醇酯二醇(PBA)为原料,采用反应湿法模压成型制得玻璃纤维增强热塑性聚氨酯(TPU)复合板材,利用力学性能测试、微观形貌表征探究了初始模压温度、模压压力、保压熟化时间三个工艺参数对复合材料力学性能的影响。结果表明,在初始模压温度60℃、模压压力2 MPa、保压熟化温度120℃时间2 h时,单体聚合反应效果好,复合材料内部TPU对纤维丝浸润程度高,纤维丝间TPU填充紧实,内部缺陷少,力学性能达到最大值。 相似文献
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以杨木粉和聚乳酸为原料,利用烷基烯酮二聚体(AKD)对杨木粉进行表面改性处理,通过模压成型工艺制备了杨木粉/聚乳酸(PLA)复合材料。以模压温度、模压压力和保压时间为正交实验因素,将复合材料力学弯曲性能和冲击强度作为评价指标,分析了模压成型工艺对复合材料力学性能的影响;在此基础上分析了AKD含量对杨木粉/PLA复合材料力学性能和吸水性能的影响。结果表明,模压工艺对复合材料力学性能的影响程度依次为模压温度、模压压力、保压时间;当模压温度为170℃、模压压力为4 MPa、保压时间为6 min/次、5次保压、AKD含量为2%~3%时,制备的杨木粉/聚乳酸复合材料力学性能和吸水性能较好。 相似文献
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采用恒速双筒毛细管流变仪研究了自制的聚1-丁烯热塑性弹性体(PB-TPE)及1-丁烯与1-己烯共聚弹性体(B-co-H)的流变性能.结果表明,相同条件下PB-TPE和B-co-H均为假塑性流体,B-co-H的非牛顿性更强,PB-TPE比B-co-H的黏流活化能高.随着1-己烯含量的增大,共聚物分子链柔顺性增加,加工性能... 相似文献
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采用浓硝酸对短切碳纤维(CF)进行表面氧化处理,利用模压法制备了热塑性酚醛树脂(PF)/CF复合材料,讨论了成型温度和保压时间等模压工艺参数对复合材料力学性能的影响。结果表明,无论保压时间和CF含量如何变化,成型温度为170℃时的复合材料弯曲强度和缺口冲击强度总体上均比成型温度为150和160℃时的高,且在成型温度为170℃的条件下,不同CF含量的复合材料力学性能在保压时间为15 min时出现最大值的次数最多。据此,确定了短切CF质量分数在5%~25%范围内的热塑性PF/CF复合材料模压成型最佳工艺参数为成型温度170℃、保压时间15 min。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure. 相似文献
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以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献
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我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉 相似文献
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