CPE专用高密度聚乙烯树脂的开发

通过工艺条件的优化和催化剂的选型,在淤浆法聚乙烯装置上开发了氯化聚乙烯(CPE)专用高密度聚乙烯(HDPE)树脂。该CPE专用HDPE树脂与同类树脂的相对分子质量及其分布相当,密度介于国产树脂A和进口树脂B之间;结晶温度接近进口树脂A,但熔融温度及热焓较进口树脂A略高;熔体流动速率和堆密度与进口树脂A相差不大;大颗粒及细粉含量都少于进口树脂,且粒径分布更集中;孔径、孔容以及比表面积与进口树脂A接近。采用该CPE专用HDPE树脂生产的制品各项性能均达到了指标要求。     

中型中空容器吹塑专用HDPE的结构与性能

从共聚单体含量、相对分子质量、力学性能、熔融结晶性能、流变性能等分析了国产与进口中型中空容器吹塑专用高密度聚乙烯(HDPE)的性能差异。结果表明:HDPE HXM50100N的重均分子量更高,相对分子质量分布较宽,刚性突出,弯曲模量达到1 430 MPa,且熔体强度高。     

橡改型CPE专用HDPE树脂剖析

通过熔体流动速率仪、梯度密度计、差示扫描量热仪、凝胶渗透色谱仪、物理吸附分析仪、粒度分析仪、扫描电镜等分析了橡改型氯化聚乙烯(CPE)专用高密度聚乙烯(HDPE)树脂的基本物理性能、热性能、结构、表面形貌等。结果表明,橡改型CPE专用HDPE树脂具有低蜡含量、中等重均相对分子质量、较窄相对分子质量分布且呈单峰分布、高熔点、高结晶度等特点;具有较大的比表面积、细粉(粒径小于125μm)和粗颗粒(粒径大于500μm)含量较低,表面呈微孔结构;国产料具有更大的平均粒径、孔容。     

氯化聚乙烯专用HDPE6800CP的结构与性能

中国石油化工股份有限公司北京燕山分公司开发的氯化聚乙烯(CPE)专用高密度聚乙烯(HDPE)6800CP相对分子质量适中,相对分子质量分布较窄,具有适宜的密度、熔体流动速率、结晶度,均匀的粒径分布,适于生产CPE.6800CP氯化过程工艺平稳,反应压力、时间及氯化过程能耗、物耗与进口同类产品相当:采用6800CP生产C...     

耐热聚乙烯管材料的支化结构研究

通过核磁共振碳谱、动态流变仪、差示扫描量热仪等对基本性能指标相近的国产和进口耐热聚乙烯(PE-RT)管材料的支化结构进行了研究。结果表明:国产和进口PE-RT管材料熔体流动速率和密度相当,力学性能接近,国产料刚性稍高,韧性略低,相对分子质量略低,相对分子质量分布略宽。与进口料相比,国产PE-RT管材料的共聚单体含量低,平均乙烯序列长度略高,平均丁烯序列长度略低,导致其黏流活化能低于进口料的。国产料高温熔融峰峰温较高。     

200L桶用HDPE中空容器专用树脂性能研究

从力学性能、相对分子质量分布、毛细管流变曲线、差示扫描量热法曲线及参数、熔体强度等方面分析了国产和进口高密度聚乙烯(HDPE)中空容器专用树脂的性能差异。结果表明:进口树脂TR571具有较好的刚性和韧性,常、低温冲击强度分别达到56.0,35.2 kJ/m~2,相对分子质量较大;国产树脂2的相对分子质量分布指数与抗氧化性能优异,其中抗氧化诱导时间在210℃的条件下达到39.8 min,熔体强度也明显高于国产树脂1,同时具有良好的结晶性能。     

不同粒径的PP粉的相对分子质量及其分布、结晶性能和力学性能

采用差示扫描量热仪和凝胶渗透色谱仪研究了PP粉粒径大小对其相对分子质量及分布、结晶行为和力学性能的影响。结果表明,粒径大小对PP粉的相对分子质量及分布、结晶温度、结晶速率、成核能力、力学性能等均有明显的影响。随着粒径的减小,PP粉的数均相对分子质量下降,相对分子质量分布变宽,熔体流动速率逐渐增大;结晶温度和结晶起始温度升高,成核能力增加,起始结晶速率增大,晶粒更加细化均匀;但其拉伸强度和缺口冲击强度有不同程度的下降。     

中空容器专用HDPE树脂的结构与性能

分析了进口和国产中空容器专用高密度聚乙烯树脂的基本性能、毛细管流变性能、动态流变性能、熔体强度。结果表明:进口树脂具有相对分子质量分布较窄、支化度较高、耐环境应力开裂性能优异的特点;相对分子质量分布较宽的国产树脂由于高相对分子质量尾端含量高而具有较高黏性、较低弹性,高剪切速率下黏度大,熔体可拉伸性能不如进口树脂。     

小中空容器专用双峰HDPE HD5503GA的结构与性能

采用高温凝胶色谱仪、高压毛细流变仪、差示扫描量热仪等分析了国内首个小中空容器专用双峰高密度聚乙烯(HDPE)HD5503GA的结构与性能,并与小中空容器专用进口双峰HDPE及国产单峰HDPE进行了比较。结果表明:HD5503GA具有加工性能好、相对分子质量分布宽、耐环境应力开裂性好及刚性强的特点,其耐环境应力开裂时间是国产单峰HDPE的16.00倍,是进口双峰HDPE的1.75倍,刚性较国产单峰HDPE高57%以上,与进口双峰HDPE相当;与国产单峰HDPE相比,可降低加工温度10～20℃,且制品表面致密,印刷性好,HD5503GA的加工性与进口双峰HDPE接近,更适宜于高腐蚀性及高极性液体的包装。     

过氧化物对PP纤维料性能影响对比

采用化学降解法，探究了过氧化物对聚丙烯(PP)纤维料性能的影响。选取2种不同的过氧化物(过氧化物A和过氧化物B),对比其对PP纤维料熔体流动速率(MFR)、力学性能、熔融、结晶、相对分子质量分布、气味等的影响。结果表明：随着过氧化物质量分数的增加，MFR明显增大，明确了改进PP纤维料性能的最佳固体过氧化物添加量。相同有效浓度下，过氧化物A与过氧化物B的相对分子质量分布、气味、30 min内热稳定性能表现相当。过氧化物A的质量分数在0.13%～0.17%时PP纤维料力学性能改善较佳。     

钢塑复合管专用交联HDPE的研制

研制了钢塑复合管专用交联高密度聚乙烯(HDPE),并研究了其性能。结果表明．交联后的HDPE具有更加优异的力学性能;随着交联剂(VS—1)用量的增加,交联HDPE的拉伸强度、冲击强度、凝胶率增加,但其断裂伸长率和流动性下降,当VS—l质量分数为1．8％时,交联HDPE的性能最佳：拉伸强度为40．8MPa,冲击强度为117J／m^2,凝胶率为73．8％,断裂伸长率为280％,熔体流动指数为0．3g／10min;将5000S与2480共混,并添加质量分数不低于1．0％的流变剂YL—1,其加工流动性最佳;用二月桂酸二丁基锡作催化剂使HDPE的交联反应在5h后就完成了90％以上．比不加催化剂提前15h。     

用PE改进UHMPE流动性的研究

选用不同牌号的高密度聚乙烯(HDPE)和低密度聚乙烯(LDPE)作为超高摩尔质量聚乙烯(UHMWPE)的流动改性剂，通过对共混物流变转矩、熔体质量流动速率及力学性能的分析；探讨了配比对UHMWPE／PE共混物流动性的影响。结果表明：用中等摩尔质量的PE改善UHMWPE的加工流动性效果较好，流动性越好的中等摩尔质量PE对UHMWPE的流动性改善效果也越显著；但对共混物力学性能的不利影响也越大。     

基于相对分子质量分布指标的HDPE生产过程模拟

提出一种以相对分子质量分布为指标,关联熔体流动速率(MFR)的高密度聚乙烯(HDPE)工业生产过程流程模拟方法.基于Innovene S HDPE装置工业生产中的聚合过程,采用流程模拟软件Aspen Plus Polymers建立基于严格过程机理的HDPE过程框架模型,结合工业操作参数及实验数据,计算聚合物相对分子质量...     

氯化聚乙烯专用HDPE的结构与性能研究

剖析了三种市场上常见专用料的摩尔质量及其分布、结晶性能、低聚物含量、粒径分布、比表面积、微观结构,提出氯化聚乙烯专用料应该具有中等摩尔质量、窄摩尔质量分布及较好的结晶性能。为保证高的氯化效率,专用料还应具有窄的粒径分布、较低的低聚物含量、较大的比表面积和孔容。同时通过旋转流变仪温度扫描的方式研究了专用料流变性能的温度依赖性。小于220℃时,随温度升高,三种专用料的黏度减小,损耗角增大;在220～230℃之间,三种专用料都发生了一定程度交联,表现为黏度增大,损耗角减小。     

Influence of grafting formulations and extrusion conditions on properties of silane‐grafted polypropylenes

The melt grafting of unsaturated silanes onto powdered polypropylene (PP) in a Haake TW100 twin‐screw extruder and curing in hot water were studied. The influence of grafting formulations and extrusion conditions on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. The gel percentages of methacryloylpropyltrimethoxysilane (VMMS)‐grafted PP were markedly higher than those of vinyltriethoxysilane (VTES)‐ and vinyltrimethoxysilane (VTMS)‐grafted PP, while significantly less degradation of PP during grafting was observed for VMMS‐grafted PP. When benzoyl peroxide (BPO) was used as an initiator, no degradation of PP during grafting was observed, and the melt flow rates of grafted PP decreased with increasing BPO concentration. In contrast, use of dicumyl peroxide (DCP) as an initiator resulted in severe degradation of PP, and the melt flow rates of grafted PP increased gradually with increasing DCP concentration. BPO resulted in higher gel percentages than those of DCP at a fixed initiator concentration. Introduction of styrene into the grafting system greatly improved the gel percentage of crosslinked PP and reduced the degradation of PP during grafting. The optimum molar ratio of styrene to monomer is at about 1.5:1. Relatively low processing temperatures and high screw speeds are favorable. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1233–1238, 2000     

Simultaneous enhancement of dielectric and mechanical properties of high‐density polyethylene/nitrile rubber/multiwalled carbon nanotube composites prepared by dynamic vulcanization

Polymer dielectric composites, which possess high dielectric and loss suppression with excellent mechanical properties, are of crucial importance in practical applications. Herein, high‐density polyethylene/nitrile rubber/multiwalled carbon nanotube (HDPE/NBR/MWCNT) composites were fabricated by the dynamic vulcanization (DV) technique. The effect of DV on the structure and properties of HDPE/NBR/MWCNTs was systematically investigated. The results illustrate that the DV technique combines the advantages of the crosslinked phase and melt processability of thermoplastics. With the increase of dicumyl peroxide content, the dielectric permittivity and the mechanical properties clearly increase, due to a better compatibility and dispersibility achieved by DV. More importantly, a continuous decrease of dielectric loss and conductivity are observed with the increase of dicumyl peroxide content. These can probably be assigned to the combination of better dispersion and slower chain mobility of the NBR phase induced by crosslinking. © 2020 Society of Industrial Chemistry     

Functionalization of high density polyethylene in melt state through ultrasonic initiation and its effect on mechanical properties of glass fiber reinforced composites

Summary Functionalization reaction of high density polyethylene (HDPE) with γ-methacryloxy-propyltrimethoxysilane (MAS) or with MAS and MAH performed in melt state through ultrasonic initiation by a laboratory-scale ultrasonic extruding reactor was studied in this paper. The effect of ultrasonic intensity on the percentage of grafting and melt flow rate of the functionalized products was investigated. The results show that by imposing ultrasonic vibration during melt-extruding process, the scission of HDPE chain bonds can be caused to form macroradicals, the functionalization reaction of HDPE with MAS or with MAS and MAH can be realized. The percentage of grafting and the melt flow rate of the functionalized products depend upon the ultrasonic intensity and reaction temperature. The fuctionalization reaction of HDPE with MAS can be promoted by adding a second grafting monomer MAH. The ultrasonic-induced products have a higher reactivity with the coupling agents coated on the surface of glass fibers, the mechanical properties of the composite improved by the ultrasonic induced product are higher than that of by peroxide initiated product and the mechanical properties of HDPE/GF composite modified by HDPE-g-MAH-MAS are higher than that of by HDPE-g-MAH. The SEM experimental results indicate that an oriented crystal layer exists between the interface of glass fiber and the HDPE matrix, the interfacial bonding strength is the determining factor of the formation of the oriented crystal layer.     

Shear and elongational flow properties of peroxide‐modified wood/low‐density polyethylene composite melts

Adding fillers to a polymer melt may result in a strain softening behavior in elongational flow in long‐chain branched materials, showing strain‐hardening behavior when compared with unfilled one. To improve the strain‐hardening properties in wood/LDPE composites, the effect of peroxide concentration on both the molecular architecture and molar mass distribution, and the rheological quantities in shear and elongation is studied. Addition of wood flour increases the viscosity according to a logarithmic mixing rule, as expected from the large particle size and the filler fractions used. The peroxide has multiple effects on the molar architecture of the polymer. First, a gel fraction of cross‐linked material is formed, the concentration of gel being dependent of the amount of peroxide used. Second, a higher molar mass component is detected, leading to higher value of M_w and to a broader molar mass distribution. Finally, the degree of long‐chain branching unexpectedly decreases with increasing peroxide content. The changes in molecular architecture are hardly influenced by addition of the wood flour. The peroxide treatment leads to an improved strain‐hardening behavior, detected by elongational viscosity and melt strength measurements. However, the addition of wood flour decreases the amount of strain hardening.POLYM. COMPOS., 33:2084–2094, 2012. © 2012 Society of Plastics Engineers     

9455F与国内外HDPE膜材料的结构对比及剖析

通过凝胶渗透色谱、差示扫描量热、力学性能、X射线衍射和流变仪等分析手段,研究了国产和进口薄膜级高密度聚乙烯的结构和加工性能。结果表明,进口的膜料相对分子质量呈现双峰分布,具有良好的力学性能和加工性能;国内产品以单峰产品为主,综合性能与进口产品有一定的差距。