宽峰高相对分子质量高密度聚乙烯专用料的研制

通过淤浆法小试聚合装置合成了不同相对分子质量的高密度聚乙烯粉末,对聚合工艺条件对产物物性的影响进行了研究.同时.考察了不同相对分子质量的聚乙烯共混合成宽峰聚乙烯专用料的规律.结果表明:通过调整聚合工艺条件.在淤浆法小试聚合装置聚合产物的相对分子质量可调;不同相对分子质量的聚乙烯粉末共混可以制备宽峰HDPE:合成的宽峰HDPE专用料的综合力学性能优良,在树脂研究院进行加工,性能良好.     

HDPE生产工艺进展

分析了高密度聚乙烯(HDPE)生产工艺现状和技术特点,淤浆聚合工艺是我国HDPE最主要的生产技术。利用釜式淤浆法工艺特点可开发双峰或多峰产品以实现其机械性能和加工性能的平衡;利用环管淤浆法工艺特点开发高性能管材料和宽相对分子质量分布产品;利用气相法工艺单线生产能力大的特点稳定生产通用产品;利用溶液法工艺产品均一性好、切换容易的特点开发高附加值特色产品。建议结合装置特点开发高性能HDPE。     

釜式淤浆工艺小中空容器专用HDPE的结构与性能

分析了釜式淤浆工艺生产的小中空容器专用高密度聚乙烯(HDPE)的性能特点、结构特性以及加工性能。结果表明:釜式淤浆工艺小中空HDPE具有较宽的相对分子质量分布及优异的耐环境应力开裂性能,与环管淤浆工艺产的HDPE相比,釜式淤浆工艺的加工条件高。     

“双组分纤维用HDPE 1508S的开发”项目通过鉴定

中国石油化工股份有限公司(简称中国石化)北京燕山分公司的科研和生产技术人员在140kt/a的淤浆法高密度聚乙烯(HDPE)装置上,通过科研攻关和工艺调整,成功开发出双组分纤维专用HDPE1508S,并于2012年7月通过中国石化组织的鉴定。HDPE1508S具有相对分子质量分     

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。     

双峰高密度聚乙烯树脂的开发前景

HDPE装置采用淤浆法生产高密度聚乙烯,描述了双峰高密度聚乙烯树脂的特点,介绍了双峰HDPE产品物性参数、聚合工艺和质量指标,概括了影响双峰高密度聚乙烯树脂物理性质的三个主要因素(聚合方式、所用共聚单体、所用稳定剂),阐述了双峰高密度聚乙烯树脂的研制开发前景。     

纯净水瓶盖专用树脂HDPE 5603JP的开发

采用了BCE催化剂,利用小试装置考察了氢气和1-丁烯对该催化剂催化乙烯聚合的影响。并将该催化剂用在淤浆法聚乙烯生产装置上,生产了纯净水瓶盖专用高密度聚乙烯(HDPE)5603JP。测试结果表明,该树脂具有适宜的密度、熔体流动速率、力学性能和卫生性能,适合生产瓶盖。生产的瓶盖产品各项性能也与国外原料生产的瓶盖产品相当。     

Basell公司新型HDPE催化剂工业化

Basell聚烯烃公司已将用于高密度聚乙烯(HDPE)生产的Advent C新型铬催化剂工业化。Basell公司称,该催化剂可以作为气相和淤浆工艺中钛基催化剂的替换物。虽然为了获得想要的HDPE性能,要求某些不同的操作条件,但在淤浆或气相工艺中使用这种新型催化剂不需要特殊的设备。这种铬基催化剂可以一步生产出具有宽相对分子质量分布的HDPE,而     

HDPE管材专用料质量产量影响因素及改进

分析了北京燕山石油化工有限公司淤浆法高密度聚乙烯装置生产管材专用料过程中影响产品质量及产量的因素,提出了通过改进有关工艺条件提高产量、质量的途径。     

不同工艺生产的高耐压等级管材专用HDPE的结构与性能

对比了采用不同工艺生产的高耐压等级管材专用高密度聚乙烯(HDPE)的结构与性能。结果表明:采用淤浆工艺生产的HDPE的相对分子质量分布较宽且呈双峰,在生产高耐压等级管材及大口径管材方面有优势;采用气相工艺生产的单峰HDPE的相对分子质量分布较窄,影响其长期使用性能,尤其在等级升级上存在困难;采用气相工艺生产的双峰HDPE所用催化剂为茂金属双活性中心催化剂,树脂的相对分子质量分布较窄,低相对分子质量组分含量较低,但其较厚晶片含量最高,长链支化最多,两者互补使其性能接近PE100+级水平。从催化剂及聚合工艺两方面研究,采用气相工艺生产的双峰HDPE的耐压等级上升空间很大,应该能够达到或超过PE100+级的水平。     

Physical properties of extended-chain high-density polyethylene

Extended-chain high-density polyethylene prepared through crystallization at high pressure is substantially stiffer and somewhat stronger than normal folded-chain HDPE. With weight-average molecular weight in the range normal for molding or extrusion resins, the extended-chain material is inductile and brittle; but with molecular weight near 2,000,000, the resin can be rigid and tough. This rigid, tough material can be converted to articles through some of the solid-state processes developed for metals. The volume–temperature behavior of HDPE at 5000 atmospheres appears to reflect a polymorphic transition between orthorhombic and triclinic phases.     

Use of radiation-grafted polyethylene in dialysis of low molecular weight metabolites

Radiation-induced graft copolymerization of styrene/maleic anhydride (Sty/MAn) binary monomers into high-density polyethylene (HDPE) has been studied. The optimum conditions under which a high grafted yield is obtained and the grafting process proceeds homogeneously have been determined. A suitable solvent for the grafting process is acetone for a (Sty/MAn) composition of (70/30 mol%). The permeability of low molecular weight metabolites (urea, creatinine, uric acid, glucose and phosphate salts) through the untreated and treated grafted HDPE membranes has been studied. The hydrophilicity of the membrane, the degree of grafting and the molecular weight and chemical structure of the metabolites have a great influence on the transport properties of the membrane. For all solutes investigated, the permeability increases with the degree of grafting. The basic metabolites show higher permeation rates through the modified membrane compared with that for the acidic metabolite, especially phosphate salts. The permeabilities of vitamin B₁₂, bovine albumin and KCl through the treated grafted membranes have been measured and those of the high molecular weight compounds are low. © 1999 Society of Chemical Industry     

Shear-induced epitaxial crystallization in injection-molded bars of high-density polyethylene/isotactic polypropylene blends

As a continuation of our previous works on exploring shear-induced epitaxial crystallization of polyolefin blends during practical molding processing [Na et al. Polymer 2005; 46, 819 and 5258], the present study focused on the importance of molecular weight on the formation of epitaxial structure in injection-molded bars of high-density polyethylene (HDPE)/isotactic polypropylene (iPP) blends. By choosing two kinds of HDPE and two kinds of iPP with high molecular weight or low molecular weight, four blends with different molecular weight combinations can be designed. After making the blends via melt mixing, the injection-molded bars were prepared in a so-called dynamic packing injection molding equipment where repeated shearing was imposed on the melts during the solidification stage. Crystal structure and orientation were estimated mainly through 2D-WAXD. Our results indicated that an appropriate matching of low molecular weight HDPE and high molecular weight iPP was more favorable for epitaxial crystallization than other component matches. The effects of orientation and epitaxy on the re-crystallization behaviors of polyolefin blends have been elucidated in detail through PLM experiments. Moreover, epitaxy has been proved to play a positive effect in determining the ultimate mechanical properties of injection-molded bars.     

聚乙烯原料对高密度聚乙烯土工膜性能的影响

本实验采用吹塑成型工艺,以不同牌号的聚乙烯(PE)树脂为原料生产2 mm厚度双光面高密度聚乙烯(HDPE)土工膜,研究PE原料对HDPE土工膜性能的影响。结果表明:中密度聚乙烯(MDPE)土工膜综合性能优异,主要是由其特有的分子结构(如分子量分布双峰性、α烯烃长支链)所决定的;不同PE原料氧化诱导时间不同,可通过调节含抗氧剂色母料(或抗氧剂)的含量,使HDPE土工膜氧化诱导时间达到要求;HDPE土工膜在焊接时应根据PE材质的不同而选择不同的焊接条件。     

Effect of small amount of ultra high molecular weight component on the crystallization behaviors of bimodal high density polyethylene

In order to clarify the effect of high molecular weight component on the crystallization of bimodal high density polyethylene (HDPE), a commercial PE-100 pipe resin was blended with small loading of ultra high molecular weight polyethylene (UHMWPE). The isothermal crystallization kinetics and crystal morphology of HDPE/UHMWPE composites were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. The presence of UHMWPE results in elevated initial crystallization temperature of HDPE and an accelerating effect on isothermal crystallization. Analysis of growth rate using Lauritzen-Hoffman model shows that the fold surface free energy (σ_e) of polymer chains in HDPE/UHMWPE composites was lower than that in neat HDPE. Morphological development during isothermal crystallization shows that UHMWPE can obviously promote the nucleation rate of HDPE. It should be reasonable to conclude that UHMWPE appeared as an effective nucleating agent in HDPE matrix. Rheological measurements were also performed and it is shown that HDPE/UHMWPE composites are easy to process and own higher melt viscosity at low shear rate. Combining with their faster solidification, gravity-induced sag in practical pipe production is expected to be effectively avoided.     

The separation of SEC curves of HDPE into flory distributions

A technique is reported here whereby molecular weight distribution curves from size exclusion chromatography (SEC) obtained on high-density polyethylene (HDPE) can be deconvolved into a series of Flory-distribution curves using a commercially available computer software system. Our analysis has shown that five to seven individual Flory distributions describe HDPE with better than a 99.9% degree of fit. We impute from this that upon taking proper precautions, we can consider these HDPE resins to be derived from at least this number of distinct catalyst sites and, furthermore, that modification of the sites will lead to a modification of the resultant resin. © 1993 John Wiley & Sons, Inc.     

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。     

阻燃高密度聚乙烯的研制

研制了阻燃高密度聚乙烯（ＨＤＰＥ）。讨论了含卤阻燃剂、无机阻燃剂、稳定剂、ＰＥ－Ｃ和不同分子量的基础树脂对阻燃ＨＤＰＥ的阻燃性和力学性能的影响。     

Functionalization of polyolefins with maleic anhydride in melt state through ultrasonic initiation

The functionalization reaction of high-density polyethylene (HDPE), linearly low-density polyethylene (LLDPE), polypropylene (PP) and EPDM rubber with maleic anhydride (MAH) in melt state through ultrasonic initiation was studied. The effect of ultrasonic intensity on the percentage of grafting, viscosity-average molecular weight, melt flow rate and gel content of the functionalized products were investigated by means of chemical titration, Fourier-transform infra-red spectroscopy (FT-IR), intrinsic viscosity and melt flow rate, etc. The molecular structures of the functionalized products prepared via ultrasonic initiation and via peroxide initiation were characterized by ¹H NMR spectroscopy. The results show that the functionalization reaction of HDPE, LLDPE and EPDM with MAH can be realized by ultrasonic initiation. This reaction mainly consists of the chain scission under ultrasonic irradiation, the end chain reaction of the produced macroradicals with MAH, and the terminated reaction of the produced succinyl radicals with the macroradicals or H* radicals through recombination or dismutation. The functionalized product through ultrasonic initiation mainly consists of the products containing an anhydride ring attached to the chain terminus. And the products prepared through peroxide initiation mainly contain an anhydride ring grafted on the side chain.