密度梯度柱法测定聚乙烯树脂密度

采用密度梯度柱法测定聚乙烯树脂的密度,研究影响该方法测定聚乙烯树脂密度准确性的因素.实验结果表明:样品的处理方式、密度梯度柱的使用温度、密度梯度柱的配制效果等因素均可对测试结果造成影响.针对这些影响因素,提出了相应措施,并确定了适用于测定密度范围(0.9530±0.0030)g·cm-3高密度聚乙烯树脂密度梯度柱的配制...     

密度天平法测定聚乙烯树脂密度方法的探讨

通过试验考察了密度天平法测试聚乙烯树脂密度的重复性和准确性, 同时对比了密度梯度法测定聚乙烯密度的结果,两种方法测试结果能满足现密度方法要求的准确度和精密度范围,重复测定两结果之差：高密聚乙烯树脂≤0.0005 g/cm3,低密聚乙烯树脂≤0.0003 g/cm3。两种方法可以互替,相互补充,并讨论了影响密度天平法测定因素。     

3K碳纤维拉伸性能测试方法的重复性和再现性

利用实验室循环比对试验的方法,研究了3K碳纤维拉伸性能试验方法的重复性和再现性,丰富了拉伸性能试验方法精密度数据,为准确测定和评价碳纤维拉伸强度和模量提供了科学的依据,为ISO标准和国标的制修订进一步积累了数据。     

测量系统重复性与再现性在100kW叶片质量管理中的应用

100kW叶片根部O型圈位置为叶片安装受力的关键部位,因而其平整度是重点控制的关键尺寸。以此为例进行测量系统重复性与再现性的分析。将测量系统的重复性与再现性(GR&R)等测量指标运用到产品质量管理之中。对测量数据进行分析,可以确定测量系统误差原因,找到改进方法,提高产品的测量精度,确保制造的产品符合要求。     

玻璃表面雾度测量系统重复性和再现性分析

简要介绍了玻璃表面雾度测量系统的影响因素,采用均值极差法对玻璃表面雾度测量系统进行分析,并对该测量系统提出改进建议。     

浅谈煤发热量统检中Qb的重复性与再现性

弹筒发热量测定的重复性与高位发热量的一致，为１５０Ｊ／ｇ；在统检时，由于全硫为一确定真值，其再现性仍为３００Ｊ／ｇ。     

密度梯度柱法测定聚乙烯密度的不确定度评定

采用《测量不确定度评定与表示》对密度梯度柱法测定聚乙烯密度的不确定度进行了评定。分析了不确定度的主要来源,包括标准曲线引入的不确定度、测量重复性引起的不确定度、温度不确定度及标准浮子的不确定度,并评估了一个样品测量结果的合成标准不确定度和扩展不确定度。     

聚丙烯HT40S熔融指数测定(MFR)重复性和再现性的研究

就HT40S牌号热熔性塑料熔融指数的测定,通过优化分析操作条件,如试样质量、负荷加载时间、试验温度恒定、试样压实程度等方面,进行了精细化研究性试验,总结出HT40S牌号热熔性塑料熔融指数测定的重复性和再现性,用于指导实际分析工作。     

密度梯度柱配制方法的改进

针对塑料密度这一重要的物性参数的密度梯度法测定，从理论上对影响密度梯度柱配制过程的各个方面进行了分析；对密度梯度与高度的线性关系进行了理论的推导；发现采用国标方法配制密度梯度柱的不足之处，对当前国标中轻、重溶液密度和体积的计算公式进行了修正，使用推导出的公式后，可以使所配制的梯度管的密度梯度与预期的结果十分相近，避免了配制失败的可能性；对配制过程中的注液速度、搅拌速度及配制的密度范围等需要控制的条件进行了详细的分析，并推荐了改进的配制方法。     

聚乙烯基础树脂由低密度向高密度切换的技术

详细阐述了中原聚乙烯装置基础树脂由低密度DGM－1820向高密度DGM－6182切换的技术,介绍了两次切换的工艺过程、状态参数,分析了切换过程中出现的问题及解决方法。     

制备氯引发PE接枝苯乙烯/顺丁烯二酸酐

为提高氯化原位接枝过程中聚乙烯(PE)接枝顺丁烯二酸酐(MAH)的接枝率,加入了第二单体苯乙烯(St).以FTIR,1H-NMR、GPC及凝胶含量研究PE氯化原位接枝MAH/St接枝共聚物(PE-cg-(MAH/St)的结构.实验结果表明:第二单体St的加入可以明显提高MAH的接枝率,同时没有交联结构的产生.研究了反应温度、单体配比、单体总质量分数、氯气流速等对接枝产物PE-cg-(MAH/St)接枝率的影响,并对接枝物的热性能进行了探索.当反应温度控制在80～90℃,MAH/St单体比例为9:7,单体总量16份,氯气流速29 mmol/min,MAH的接枝率可达3.56％.     

燃气用聚乙烯(PE)新材料与试验新方法

介绍了燃气用聚乙烯(PE)新材料与试验新方法的发展状况。原材料制造商推出适用于非传统管道铺设的PE100-RC材料和用于生产大尺寸管材的低熔垂材料。缺口圆柱棒(CRB)试验和应变硬化模量(SH)试验能更迅速地评价材料的SCG性能。通过建立简支梁冲击试验的临界温度与S4临界温度的相关性,研究出一种快速评价PE快速开裂(RCP)性能的小尺度方法。     

聚乙烯给水管的性能及应用

介绍聚乙烯给水管的性能和施工工艺,详细叙述了连接方式、连接方式的适用条件以及接头质量的检查方法,讨论分析了聚乙烯（PE）给水管的施工中常见的问题及应采取的措施,给出了施工、维护中的几点经验和建议。     

利用高密度聚乙烯装置生产线型低密度聚乙烯的相关研究

随着我国经济实力的飞速发展,对线型低密度聚乙烯的需求也有了很大的提升,相关部门必须对高密度聚乙烯装置生产线型低密度聚乙烯工艺给予足够的重视,并且加大对催化剂的研究力度。因此,主要对高密度聚乙烯装置生产线型低密度聚乙烯工艺进行了简要分析,阐述了相关催化系统,并且对生产工艺装置与主要生产流程进行了研究分析。     

Preparation and Characterization of Bioblends from Gelatin and Linear Low Density Polyethylene (LLDPE) by Extrusion Method

Abstract

Bioblends are composites of at least one biodegradable polymer with a non-biodegradable polymer. Successful development of bioblends requires that the biodegradable polymers be compatible with other component biodegradable/synthetic (non-biodegradable) polymers. Bioblends from LLDPE and gelatin were prepared by extrusion and hydraulic heat press technique. The gelatin content in the bioblends was varied from 5 to 20 wt%. Various physico-mechanical properties such as tensile, bending, impact strength (IS), thermal ageing and soil degradation properties of the LLDPE/gelatin bioblends with different gelatin contents were evaluated. The effect of thermal ageing on mechanical properties was studied. The mechanical properties such as tensile modulus (TM), bending strength (BS), bending modulus (BM) were found to increase with increasing gelatin content up to 20 wt%, however tensile strength (TS) and elongation at break (%E _b) were decreased with increasing gelatin content. Impact strength value increased with increasing gelatin content up to 10 wt% and then decreased slightly with increasing gelatin content. The blend containing 20 wt% gelatin showed relatively better mechanical properties than other blends. The values of TS, TM,%E _b, BS, BM and IS for the bioblend with 20 wt% gelatin content are 5.9MPa, 206.3MPa, 242.6%, 12.1MPa, 8 MPa and 13.7 J/cm², respectively. Water uptake increases with increasing soaking time in water and weight loss due to soil burial also increases with increasing gelatin content in the blends but both are significantly lower than that of pure gelatin sheet. Weight loss values after thermal ageing increase with time, temperature and increasing gelatin content in the blend but are much lower than pure gelatin. Mechanical properties such as TS, TM are increased and %E _b is decreased after thermal ageing at 60°C for 30 min. Consequently, among all of the bioblends prepared in this work the blend having 20% gelatin content yields properties such that it can be used as a semi-biodegradable material.     

Heat Shrinkable Polymer Blends Based on Grafted Low Density Polyethylene and Chlorosulfonated Polyethylene (Part-II)

Abstract

Heat shrinkability of the polymer which depends on elastic memory can be introduced into the system in the form of an elastomeric phase. The present study deals with the measurement of heat shrinkability of the blend of grafted polyethylene and CSM. Interchain crosslinking between grafted polyethylene and elastomer improved the shrinkability. Maleic anhydride and glycidyl acrylate is used as grafting materials. Glycin and 4 4prime; diamino diphenyl sulphone is used as coupling agents. Maximum amount of crosslinking is obtained when glycidyl acrylate is used as grafting agent Minimum amount of interchain crosslinking is observed when 4 4prime; diamino diphenyl sulphone is used as coupling agent. Probable interactions of rubber and plastic phase are confirmed by IR spectroscopy. Extraction of the elastomeric phase is restricted due to interchain crosslinking as confirmed by SEM study which is more prominent in the case of glycidyl acrylate grafted LDPE.