聚乙烯加工流变改性剂对LLDPE／HDPE流变性能的影响

本文介绍在ＬＬＤＰＥ（７０４７）／ＨＤＰＥ（６０９８）共混物（重量比为９０：１０）中加０．５％、１．０％、１．３％、１．５％、２％的聚乙烯加工流变改性剂，采ＸＬＹ－Ⅱ型毛细管流变仪测其流变性能。结果表明，加入ＱＬＹ树脂后，该本系的剪切速率增，表观粘度下降，活化降低，熔体乃属假塑性流体。     

LLDPE护套料专用树脂性能研究

ＤＦＤＡ－７０４２ＥＬＬＤＰＥ护套料专用树脂,与ＤＦＤＡ－７０４２ＬＬＤＰＥ通用树脂相比,前者不仅保持了ＬＬＤＰＥ通用树脂的技术性能,而且有效地解决了ＬＬＤＰＥ通用树脂挤出中的熔体破裂问题,使挤出物获得了良好的表面光洁度,制成的ＬＬＤＰＥ护套料,各项技术性能均满足ＧＢ１５０１５－１４国家标准中ＬＤＨ的要求,其加工性能与国际同类先进护套料相当。     

通信电缆光缆LLDPE护套料挤出表面光洁度改性研究

ＬＬＤＰＥ具有优异的耐环境应力开裂等性能,很适合做通信电缆和光缆护套料,但熔融挤出时,熔体易破碎,挤出物表面呈鲨鱼皮状,光洁度差。用ＰＰＷ高聚物改性ＬＬＤＰＥ制备护套料,可使挤出表面获得良好的光洁度。ＰＰＷ高聚物用量控制在１５％以下可使ＬＬＤＰＥ护套料具有优异的技术性能和良好的挤出加工特性。ＰＰＷ高聚物与国内外用于改性ＬＬＤＰＥ加工性能的聚烯烃含氟助剂相比,更具有经济性,且应用效果更好。     

CQS963线性聚乙烯炉套料流变性能分析

用高压毛细管流变仪（ＧＯＥＴＴＦＥＲＴ ＲＨＥＯＧＲＡＰＨ２００２）,在相同的实验条件下,测定国产ＣＱＳ９６３ＬＬＤＰＥ护套料,美国ＤＦＤＧ－６０９５ＬＬＤＰＥ护套料,美国ＤＦＤＤ－０５８８ＬＤＰＥ护套料。日本ＵＢＥＣ－６００Ｖ６ＬＤＰＥ护套料的流变行为,并对实验结果进行分析。     

黑色线性低密度聚乙烯护套料的开发与生产

本文简述了护套料的发展历程,评述了黑色ＬＬＤＰＥ护套料的生产工艺、配方、设备、力学性能、加工特性,表明ＬＬＤＰＥ护套料有广阔的市场前景。     

新型HDPE通信光(电)缆护套料的研制

通过对基础树脂,改性树脂的选择,进行了新型ＨＤＰＥ通信光（电）缆护套料的配方设计,并探讨了成核剂,熔体粘度调节剂等对护套料性能的影响,结果表明：成核剂的加入可使ＨＤＰＥ护套料的密度提高,熔点降低,加入熔体粘度调节剂则可使护套料的低温脆性、低温伸长率、断裂伸长率提高。新研制的ＨＤＰＥ护套料加工温度低,加工温度范围宽,既可用于通信电缆也可用于光缆外层护套材料。     

HYPPA在LLDPE中的加工应用研究

将０．５％的ＨＹＰＰＡ渗入ＬＬＤＰＥ中,造粒后进入吹膜和制成护套料进行工业应用,实验结果表明,含有ＨＹＰＰＡ的ＬＬＤＰＥ技术性能不变,但应用加工性能显著提高。     

我国黑色聚乙烯电缆护套料的研制现状

介绍了国内ＰＥ电缆护套现状及发展趋势，重点介绍了ＬＤＰＥ护套料配方中各组分的选用标准、生产工艺及一些实际应用测试指标，同时提出了生产ＰＥ电缆护套料各组分量佳配比工艺路线。     

LLDPE的改性与加工

本文简述了ＬＬＤＰＥ的特性，采用宏信科技实业公司研制的助剂作为改性剂，提高了ＬＬＤＰＥ加工质量和产量。     

PPA在LLDPE/LDPE薄膜加工中的应用

本工作以ＬＬＤＰＥ／ＬＤＰＥ共混树脂为基料，添加氟弹性体ＰＰＡ加工改性剂，采用挤出吹塑成型加工薄膜制品．ＬＬＤＰＥ／ＬＤＰＥ＝１／２为空白．添加５００ＰＰＭ的ＰＰＡ后，共混物中ＬＬＤＰＥ为１／３时，挤出机电流下降，薄膜的透光率增加，雾度降低；ＬＬＤＰＥ含量为６０％时，挤出机电流未变而产量提高，薄膜的透光率和雾度变化不大；继续增加ＬＬＤＰＥ比例时，挤出机电流和薄膜雾度增加．薄膜的拉伸性质随ＬＬＤＰＥ比例增大而显著提高，且纵横向的取向性变小．     

PVC通信电缆绝缘料流变行为的研究

本文采用毛细管流变仪对聚氯乙烯电缆料的加工流变性能进行了研究，分析并讨论了影响ＰＶＣ流变性能的各种因素。结果表明：在试验温度下，增塑ＰＶＣ的剪切应力均随剪切速率的增加而增大，但当剪切速率增加到一定程度后，剪切速率对剪切应力的影响变小；改性剂ＰＭ－１的加入可以大大降低在相同剪切速率下的剪切应力。改性剂ＰＭ－１使电缆料的剪切敏感性减小，牛顿性增强。虽然ＰＭ－１不能改变临界剪切应力值，但却使当临界剪切应力相应的熔体粘度减小，即临界剪切速率增大，这在实际生产过程中是十分有用的，即可以提高挤出速度而不致于产生熔体破裂。分子量减小，熔体表观粘度明显减小。熔体表观粘度随温度的升高而逐渐减小。     

Study on Rheology of LLDPE under Compound Stress Field of Vibration and Shear in Extrusion Molding

In this article, a new equipment was self-developed to study the effect of compound stress field of vibration and shear on rheological properties. Using the special equipment, study on the rheological properties of LLDPE under single vibration field, single shear field and compound stress field was respectively carried out. The experimental results show that the changes of apparent viscosity of LLDPE melt is relative to vibration frequency, vibration amplitude, and mandrel rotary speed under the compound stress field. The apparent viscosity can be reduced much more sharply in compound stress field than in the single vibration or shear field.     

LLDPE/纳米ZnO复合材料熔体流变性的研究

将纳米ZnO(或改性纳米ZnO)与LLDPE经Brabender挤出机熔融共混制备了LLDPE/纳米ZnO复合材料,采用毛细管流变仪和HAAKE转矩流变仪研究了该复合材料的熔体流变性能,讨论了纳米ZnO、改性纳米ZnO及KH550偶联剂含量对LLDPE熔体流变性能的影响。结果表明:少量纳米ZnO的加入略提高了LLDPE的表观黏度、黏流活化能和熔体的平衡转矩,改性纳米ZnO复合材料的表观黏度比未改性纳米ZnO复合材料的略低。     

共聚聚丙烯(cPP)/线型低密度聚乙烯(LLDPE) 共混体系的流变与结晶形为

用毛细管流变仪研究了共聚聚丙烯(cPP)与线型低密度聚乙烯(LLDPE)共混物熔体的流变行为.讨论了共混物的组成、切应力和剪切速率对熔体流变行为和熔体粘度的影响.测定了不同配比共混物熔体的非牛顿指数.结果表明共混物熔体属假塑性流体,但共混体系粘度随LLDPE加入量的增加变化不大.DSC结晶曲线及扫描电镜(SEM)照片表明,LDPE的加入使cPP的结晶温度变化不大,但对晶体形态有一定影响.LLDPE对cPP有一定的增韧改性作用,当LLDPE质量分数为15%时,共混物的冲击强度增幅在40%左右,而拉伸强度保持率为80%.     

Modification of recycled high‐density polyethylene by low‐density and linear‐low‐density polyethylenes

The present study investigated mixed polyolefin compositions with the major component being a post‐consumer, milk bottle grade high‐density polyethylene (HDPE) for use in large‐scale injection moldings. Both rheological and mechanical properties of the developed blends are benchmarked against those shown by a currently used HDPE injection molding grade, in order to find a potential composition for its replacement. Possibility of such replacement via modification of recycled high‐density polyethylene (reHDPE) by low‐density polyethylene (LDPE) and linear‐low‐density polyethylene (LLDPE) is discussed. Overall, mechanical and rheological data showed that LDPE is a better modifier for reHDPE than LLDPE. Mechanical properties of reHDPE/LLDPE blends were lower than additive, thus demonstrating the lack of compatibility between the blend components in the solid state. Mechanical properties of reHDPE/LDPE blends were either equal to or higher than calculated from linear additivity. Capillary rheological measurements showed that values of apparent viscosity for LLDPE blends were very similar to those of the more viscous parent in the blend, whereas apparent viscosities of reHDPE/LDPE blends depended neither on concentration nor on type (viscosity) of LDPE. Further rheological and thermal studies on reHDPE/LDPE blends indicated that the blend constituents were partially miscible in the melt and cocrystallized in the solid state.     

Comparison between a linear and a branched low-density polyethylene

Two low-density polyethylenes, a linear low-pressure (LLDPE) and a branched high-pressure (LDPE), have been compared. Their shear and extensional behavior and melt fracture phenomena have been investigated, and some mechanical and optical properties of their blown films have been measured. The rheological analysis showed major differences between the samples, both in shear viscosity and in elongational viscosity. The LLDPE exhibited two types of melt fracture, the first of which—a fine scale extrudate roughness—was not shown by the LDPE and appeared at a very low shear rate. The concomitance in LLDPE of a high shear viscosity and a low elongational viscosity and the presence of melt fracture at low shear rate resulted in its more difficult processing into film. The mechanical properties of the LLDPE film approached those of high-density polyethylene while the optical characteristics were in the range of LDPE. Such a coexistence of properties makes LLDPE an interesting material for film production.     

聚丙烯的高性能化研究

研究了玻璃纤维、线型低密度聚乙烯(LLDPE)、三元乙丙橡胶(EPDM)对聚丙烯(PP)流变性能、力学性能、热性能和硬度的影响。结果表明:玻璃纤维的加入使PP的硬度及拉伸强度增大,热变形温度提高;LLDPE与EPDM使PP的冲击强度提高;玻璃纤维、LLDPE、EPDM复配可综合提高PP的力学性能、硬度及热变形温度。     

生产电缆护套料存在的问题探讨

介绍生产电缆护套料所用F催化剂的性能，分析以往大庆线性低密度聚乙烯装置多次开发失败的原因及成功经验，对生产过程中存在的问题进行讨论。确定生产电缆护套料DFDA-7540最佳控制措施，为同类装置生产提供技术指导。