HDPE超大口径双壁波纹管专用树脂的设计

针对超大口径双壁波纹管的特定性能设计了高密度聚乙烯(HDPE)专用树脂7800M,并进行了产品质量认证.设计7800M的重均分子量为(3.0～4.5)×105,相对分子质量分布为双峰模式,分布值为40～60;共聚单体选用1-丁烯,且分布在高相对分子质量级分.质量认证结果表明:7800M设计合理,产品实现了高刚性与优异的耐环境应力开裂(ESCR)性能的合理均衡,其弯曲模量在1 400 MPa以上,ESCR(F50)在1 000h以上,可满足超大尺寸管材制品对材料的要求.性能指标符合GB/T 19472.1-2004中对埋地排水管专用树脂的要求.     

埋地排水管用HDPE的研制

根据欧洲标准,结合材料的应用性能及高密度聚乙烯（HDPE）埋地排水管不同结构壁管的成型要求,确定了6360M攻关技术指标。从制品的成型性及材料的宏观性能对树脂的微观结构要求人手,在综合考虑HDPE埋地排水管成型中的流变学、攻关技术指标要求及管材专用树脂的结构特点等基础上开发了新产品6360M。     

埋地排水管材专用聚丙烯树脂的结构与性能

利用核磁共振波谱仪、凝胶渗透色谱仪、X射线衍射仪、差示扫描量热仪、偏光显微镜及动态流变仪等研究了埋地排水管材专用聚丙烯(PP)树脂与给水管材专用PP树脂的结构与性能.结果表明:与给水管材专用 PP树脂相比,埋地排水管材专用PP树脂具有更高的相对分子质量、适宜的相对分子质量分布、合理的乙烯含量及不同的分子链序列结构.埋地排水管材专用PP树脂的弯曲模量大于1 600 MPa,简支梁缺口冲击强度大于80 kJ/m2,负荷变形温度大于100℃,具有优异的刚韧平衡性能和较高的熔体强度.     

燕化聚乙烯管材家族再添新丁

近日 ,随着HDPE6380M管材专用料通过PE80标准认证 ,标志着我国自行开发生产的双峰聚乙烯管材专用料研发生产取得了突破性进展 ,也为燕化聚乙烯管材专用料家族增添备受市场欢迎的新成员。目前 ,燕化双峰压力管材专用料6380M、通用管材专用料 61 0 0M、埋地排水管专用料 6360M研发生产处于国内领先水平 ,并可替代部分进口产品。聚乙烯 (PE)管材以其可热熔焊接、易于施工安装等卓越功能得到了各行业的青睐 ,广泛应用于市政和建筑给水、天然气输送、民用燃气输送、埋地给水系统、电线电缆护套、农用节水灌溉以及工业液体输送等众多领域。目…     

HDPE管材专用树脂的流变性能

应用动态流变仪、毛细管流变仪和转矩流变仪,对新型双峰高密度聚乙烯(HDPE)管材专用树脂 6380 M进行流变性能测试分析,并与国内外相同压力等级的HDPE管材专用树脂进行比较。结果表明,6380 M的各种流变性能与进口管材专用树脂相当,而与单峰HDPE管材专用树脂相比具有弹性模量低、零切黏度低、拉伸黏度低的流变特性,从而对其加工性能产生影响。6380 M流动性好,其临界剪切速率高,但熔体强度不及单峰HDPE。     

高密度聚乙烯6300M和2480的耐环境应力开裂性能研究

研究了成型塑料管材的两种牌号的高密度聚乙烯(HDPE)6300M和2480的耐环境应力开裂(ESCR)性能。研究中采用的测试方法为一般弯曲试片法、在管上取样的弯曲试片法和恒定压应变法-压缩环法。根据两种材料测试结果及与其他牌号HDPE测试数据比较,对他们的ESCR进行评价,并讨论和解释了HDPE结构参数,ESCR与韧性形变和脆性断裂之间的联系。     

PE100级管材专用树脂性能研究

分析了高密度聚乙烯(HDPE)管材专用树脂DGDB 2480H及典型双峰PE 100级管材专用树脂的性能。两者的力学性能相当;DGDB 2480H具有较低的剪切黏度,有利于管材的加工成型,熔体强度为1.05 MPa,与国产及进口管材专用树脂相当,比普通HDPE大,有利于大口径管材的挤出。     

硅烷交联管材专用HDPE 2300XM的性能与应用

在高密度聚乙烯(HDPE)装置上工业化开发了硅烷交联聚乙烯(PEXb)管材专用HDPE 2300XM。性能测试与应用研究表明:2300XM具有合理的熔体流动速率与密度,其物理性能、流变性能及PEXb管材性能与进口专用树脂HDPE XL6500相当,满足PEXb管材快速挤出与长期使用要求。由2300XM生产的PEXb管材通过了110℃,8 760 h静液压状态下热稳定性试验;2300XM是国内首个通过10 000 h长期静液压分级试验的冷热水用交联聚乙烯管材基础树脂,其PEXb管材最小要求强度等于10 MPa,表明2300XM为交联PE100级管材基础树脂。     

加速试验研究HDPE管材耐慢速裂纹增长性能

研究了不同浓度的壬基酚聚氧乙烯醚表面活性剂溶液对高密度聚乙烯(HDPE)管材锥体试验的影响;同时开发了一种复合表面活性剂溶液,并研究其在锥体试验和HDPE全缺口拉伸蠕变试验中的加速效果。结果表明:一般的表面活性剂溶液对HDPE管材慢速裂纹增长性能影响不大,而新开发的表面活性剂溶液相对于壬基酚聚氧乙烯醚表面活性剂溶液具有至少1倍的加速效果,极大地加速了HDPE管材的耐慢速裂纹增长性能评价试验,加快了HDPE管材专用树脂的开发工作。     

塑料市场

国内滚塑用PE树脂原料发展趋势国内大型滚塑储罐制品的市场容量约为30 kt/a,为解决该类制品对挺度的要求,加工厂家多采用添加高密度聚乙烯(HDPE)与聚乙烯滚塑专用树脂共混来解决制品挺度问题,但由于目前市场上常见的滚塑专用树脂多为密度低于0.94 g/cm3的丁烯共聚产品,致使储罐的耐环境应力开裂(ESCR)与抗冲击性能稍差,且与HDPE掺混后给原料的熔     

Modeling of the fracture mechanism of HDPE subjected to environmental stress crack resistance test

Environmental stress crack resistance (ESCR) is a commonly used test to characterize cracking failure of high‐density polyethylene in applications such as wires, cables, blow molded containers, and other rigid packaging applications. From a resin design standpoint, it is important to understand the mechanism of environmental stress cracking especially in the case of materials with significantly different ESCR values. Currently, two standard ESCR tests, ASTM D1693 and ASTM F2136, are commonly accepted to measure environmental stress crack resistance of HDPE. An accurate observation of ESC is important to understand the fracture mechanism of samples. In this study, the ESCR performance of six HDPE samples was determined per ASTM D1693. The failed specimens were further characterized by scanning electron microscopy and fractographic methodology to investigate the failure mechanism. HDPE resins with low ESCR values had crack surfaces characterized by shorter and fewer fibrils. A new empirical model to predict polymer ESCR using tie chain concentration with different integration range, and water vapor transmission rate, to characterize detergent diffusion in the crack, was developed. The proposed empirical parameter improves the prediction of ESCR. The ability to predict ESCR performance from resin properties is a beneficial tool for new product development. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

管材专用高密度聚乙烯的研究进展

综述了国内高密度聚乙烯(HDPE)的生产装置及工艺。采用双峰聚合工艺使短支链更多地分布在高相对分子质量部分是HDPE管材从PE80级升至PE100级的主要原因。管材的耐环境应力开裂性能随HDPE相对分子质量减小而下降,提高短支链含量可提高管材的耐环境应力开裂性能。HDPE的相对分子质量越高,管材抗裂纹扩展性能越好,将短支链分布在高相对分子质量端可提高抗裂纹扩展性能。     

HDPE耐环境应力开裂性能的研究及改进

对HDPE的耐环境应力开裂性能进行了研究。试验表明:采用共混及化学改性的方法,HDPE的耐环境应力开裂性能有了很大提高,为解决HDPE树脂在制作管材时出现的短时间内应力开裂问题提供了依据。     

中型散装容器专用树脂的性能

研究了中型散装容器专用树脂高密度聚乙烯QHB07的基本物性、耐紫外光老化性能、耐环境应力开裂（ESCR）性能和流变行为。结果表明：QHB07的200℃氧化诱导期超过100min;经过500h紫外光老化试验后,断裂伸长率基本无变化;ESCR可达5000h;具有良好的加工性能,能够满足生产厂家的要求。     

Polymer Network Mobility and Environmental Stress Cracking Resistance of High Density Polyethylene

Zero shear viscosity and molecular weight between entanglements (M _e ) are determined from dynamic oscillatory shear experiments. Lower M _e value means higher number of entanglements in the system and is associated with increasing strain hardening stiffness. With the understanding that strain hardening is related to environmental stress cracking resistance (ESCR) of high density polyethylene (HDPE), M _e is then related to the ESCR of several resins in this study. The inversely proportional relationship between M _e and ESCR indicates that low network mobility due to an increasing number of chain entanglements increases the ESCR of HDPE.     

Investigations of environmental stress cracking resistance of HDPE/EVA and LDPE/EVA blends

HDPE/poly(ethylene‐co‐vinylacetate) (EVA) and low‐density polyethylene (LDPE)/EVA blends were tested and compared with respect to their environmental stress cracking resistance (ESCR) using the Bell‐telephone test. The time to failure in the ESCR test improves with increasing EVA content, and considerable improvements were produced for LDPE/EVA blends while small improvements were observed for HDPE/EVA blends. Thermal, rheological, mechanical, and morphological studies were conducted which established a quantitative relationship between morphological features and composition. Furthermore, the failed specimens were further characterized by scanning electron microscopy and fractographic methodology to investigate the failure mechanism for ESCR samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39880.     

The effect of processing variables on the environmental stress crack resistance of blow-molded polyethylene bottles

The effects of blow-molding process variables on the environmental stress crack resistance (ESCR) of high-density polyethylene (HDPE) bottles were studied. Experimental design was employed to test the effect of die temperature, mold temperature, molding time, and drop time. Bottles blown at each condition were tested using the internal pressure ESCR test. Through the use of regression analysis, the effect of each variable was quantified. Increasing die temperature, mold temperature, or molding time decreased ESCR. However, increasing drop time increased ESCR.