汽车工业用共聚聚丙烯的研制

通过分子设计,确定了共聚聚丙烯中乙丙橡胶质量,乙烯含量,乙丙橡胶和共聚聚丙烯特性粘度等因素对其宏观性能的影响,并确定了各因素的最佳控制指标,成功地在生产能力在40kt/a的工业装置上研制开发了本体法工艺汽车工业用共聚聚丙烯树脂。     

抗冲击共聚聚丙烯的结构与性能

对3种抗冲击共聚聚丙烯的力学性能进行了研究,并且采用动态力学分析、二甲苯溶出、溶胶凝胶渗透色谱和核磁共振等方法分析了抗冲共聚聚丙烯结构对其力学性能的影响。结果表明:提高共聚聚丙烯中乙丙橡胶相和聚丙烯基体之间的相容性,增加橡胶相含量,增大相对分子量并使其分布较窄,增加橡胶相中乙丙无规共聚物含量均有利于提高共聚聚丙烯的冲击强度。     

聚丙烯共混改性研究新进展

概述国内外改性聚丙烯研究的新进展，介绍以共聚丙烯为基础料的共聚共混改性研究的最新成果，包括用２１种不同牌号乙丙橡胶对聚丙烯增韧的效果，并介绍用质量分数２％－１０％三元乙丙橡胶增韧的超高韧性聚丙烯合金和滑石粉填充聚丙烯复合材料等的性能。     

聚丙烯超高抗冲共聚产品SP179生产和微观分析

通过确定气相反应器中的乙烯/乙烯+丙烯和氢气/乙烯的组分,生成较多的乙丙橡胶,使聚丙烯抗冲共聚产品SP179具有较高的抗冲强度.通过对产品的微观分析,指出橡胶相含量、乙烯含量、平均橡胶粒子粒径、橡胶粒子分散情况是影响产品冲击强度的因素.     

嵌段共聚聚丙烯在连续本体聚合装置上的工艺开发

从分子设计入手，通过选择适宜的催化剂，调整工艺参数、聚丙烯相对分子质量及其分布，控制聚合物中的乙丙橡胶量及结构，在连续本体聚丙烯装置上成功开发出了刚韧性平衡的嵌段共聚聚丙烯。     

防腐蚀用改性聚丙烯塑料

以丙烯—乙烯共聚树脂和二元乙丙橡胶为改性剂与聚丙烯共混,添加无机填料,选择合适的防老体系试制出防腐蚀用改性聚丙烯板、管、管件和焊条,同时摸索了二次加工技术。防腐蚀用改性聚丙烯管经化工厂等使用,反映良好。     

透明热封聚丙烯中乙烯含量标准物质定值不确定度的评定

以乙丙丁三元共聚聚丙烯为乙烯含量标准物质定值样品,对乙烯含量测量不确定度的来源进行了分析和评定。结果表明,影响乙丙丁三元共聚聚丙烯乙烯含量标准物质不确定度的因素主要有样品均匀性、样品稳定性和各实验室定值结果的重复性。经过评定,乙丙丁三元共聚聚丙烯乙烯含量标准物质测定的不确定度为0.06,标称值为2.62±0.06。     

乙丙丁三元共聚聚丙烯中丁烯含量标准物质定值不确定度的评定

以乙丙丁三元共聚聚丙烯为丁烯含量标准物质定值样品,对丁烯含量测量不确定度的来源进行了分析和评定。结果表明,影响乙丙丁三元共聚聚丙烯丁烯含量标准物质不确定度的因素主要有样品均匀性、样品稳定性和各实验室定值结果的重复性。经过评定,乙丙丁三元共聚聚丙烯丁烯含量标准物质测定的不确定度为0.10,标称值为4.82±0.10。     

乙丙橡胶生产、市场现状及发展分析

一、乙丙橡胶概况乙丙橡胶(EPR)是继齐格勒—纳塔催化剂的发明、聚乙烯和聚丙烯的出现后问世的一种以乙烯、丙烯为基本单体的共聚橡胶,分为二元乙丙橡胶(EPM)和三元乙丙橡胶(EPDM)两大类。EPR具有许多其它通用合成橡胶所不具备的优异性能,如耐臭氧性、耐老化性、耐化学品腐蚀性     

超韧聚丙烯的结构与性能

采用扫描电子显微镜、动态力学分析仪和毛细管流变仪等研究了超韧聚丙烯(PP)的结构与性能,并与普通抗冲击共聚PP进行了对比。超韧PP中乙丙橡胶相和PP相的玻璃化转变温度差53.30℃,而普通抗冲击共聚PP中乙丙橡胶相和PP相的玻璃化转变温度差62.32℃;在相同剪切速率下,超韧PP的表观黏度小于普通抗冲击共聚PP;超韧PP在23,-20℃时的简支梁缺口冲击强度分别为70.43,8.55 kJ/m2,远高于普通抗冲击共聚PP(分别为12.00,3.69 kJ/m2)。     

热灌装瓶用聚丙烯的开发

以无规共聚聚丙烯为基础树脂,添加少量透明剂,生产出符合热灌装瓶用树脂性能要求的专用树脂：探讨了乙烯加入比例、透明剂的品种及其添加量对专用树脂性能的影响。结果表明,当总乙烯质量分数控制在1％～4％时,通过添加适宜的透明剂,可使专用树脂的性能达到国外同类产品的水平。     

抗冲聚丙烯管材专用树脂的结构与性能

研究了乙丙嵌段共聚聚丙烯(PP-B)管材专用树脂的结构与性能。PP-B具有典型的乙丙嵌段共聚物序列结构,是含有丙烯均聚物(PP-H)、乙丙橡胶(EPR)及可结晶乙丙共聚物的抗冲聚丙烯(PP);其中,均聚物与共聚物比例合理,形成的EPR多、粒径小,对提高冲击强度有利。提高PP-H的质量分数和等规指数,可有效提高PP- B的刚性。PP-B的熔点与PP-H近似;相对分子质量分布较宽,流变性能好;微观与亚微观结构合理,宏观性能优良。     

丙烯/1-丁烯无规共聚物与丙烯/乙烯抗冲共聚物的对比研究

对丙烯/1-丁烯无规共聚物(PPB)与丙烯/乙烯抗冲共聚物(PPE)的结晶行为进行对比,在等温结晶时,通过相对结晶度随时间的变化关系、等温结晶曲线等研究,表明丙烯/1-丁烯无规共聚物结晶速率明显低于丙烯/乙烯抗冲共聚物,同时丙烯/乙烯抗冲共聚物的等温结晶速率随乙烯单元含量增加没有明显降低。根据Avrami方程计算了共聚物的结晶活化能,证明丙烯/1-丁烯无规共聚物的结晶能力较丙烯/乙烯抗冲共聚物低。扫描电镜分析丙烯/1-丁烯无规共聚物在丁烯单元摩尔分数2.39%时没有韧性拉伸,而丙烯/乙烯抗冲共聚物在乙烯单元摩尔分数3%时出现韧性拉伸。     

无规共聚聚丙烯管材专用树脂的研究

对中国石化上海石油化工股份有限公司无规共聚聚丙烯(PP-R)管材专用树脂与进口产品在微观结构表征、结晶性能、流变性能、加工性能等方面进行了分析对比。结果表明:研制的PP-R专用树脂,其乙烯摩尔分数为4.3%,重均分子量为7×105左右,具有良好的力学性能及加工性能,特别是通过配方体系的优化,使其具有优异的耐热氧老化性能,满足了PP-R管材专用树脂的使用要求。     

Influence of copolymerization conditions on the structure and properties of polyethylene/polypropylene/poly(ethylene‐co‐propylene) in‐reactor alloys synthesized in gas‐phase with spherical ziegler‐natta catalyst

A spherical TiCl₄/MgCl₂‐based catalyst was used in the synthesis of polyethylene/polypropylene/poly (ethylene‐co‐propylene) in‐reactor alloys by sequential homopolymerization of ethylene, homopolymerization of propylene, and copolymerization of ethylene and propylene in gas‐phase. Different conditions in the third stage, such as the pressure of ethylene–propylene mixture and the feed ratio of ethylene, were investigated, and their influences on the compositions, structural distribution and properties of the in‐reactor alloys were studied. Increasing the feed ratio of ethylene is favorable for forming random ethylene–propylene copolymer and segmented ethylene–propylene copolymer, however, slightly influences the formation of ethylene‐b‐propylene block copolymer and homopolyethylene. Raising the pressure of ethylene–propylene mixture results in the increment of segmented ethylene–propylene copolymer, ethylene‐b‐propylene block copolymer, and PE fractions, but exerts a slight influence on both the random copolymer and PP fractions. The impact strength of PE/PP/EPR in‐reactor alloys can be markedly improved by increasing the feed ratio of ethylene in the ethylene–propylene mixture or increasing the pressure of ethylene–propylene mixture. However, the flexural modulus decreases as the feed ratio of ethylene in the ethylene–propylene mixture or the pressure of ethylene–propylene mixture increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2481–2487, 2006     

管材用抗冲共聚聚丙烯的研制

通过研究聚合、造粒生产工艺条件对管材用抗冲共聚聚丙烯(PP-B)产品性能的影响,并筛选出合适的抗氧剂体系.在工业装置上开发了PP-B管材专用树脂4240。其屈服拉伸强度超过21 MPa,低温冲击强度超过4.4 kJ/m~2,综合性能与国外同类产品相当。     

乙烯质量分数对共聚透明PP性能的影响

讨论了乙烯质量分数[ω（C2H4）]对无规共聚透明聚丙烯(PP)性能的影响,并在保证透明度的同时,提出了其加入范围。试验证明,随着ω（C2H4）的增加,无规共聚PP的屈服拉伸强度、热变形温度降低,冲击强度有了明显的提高,雾度有降低趋势。含有较高ω（C2H4）(如大于4％)的PP,具有相对较低的雾度(38％左右),是透明PP专用树脂的良好基料。添加透明剂A的无规共聚透明PP,ω（C2H4）至少在3％以上,专用树脂的透明度和其他性能良好。     

Influence of the longest ethylene and isotactic propylene sequences on crystallization elution fractionation of ethylene/propylene copolymers

Crystallization elution fractionation (CEF) is the newest crystallization-based technique for estimating the chemical composition distribution of ethylene/1-olefin copolymers. Understanding the separation mechanism of CEF for ethylene/propylene copolymers over their full compositional range is challenging because the crystallizabilities of the copolymer chains depend on the longest ethylene sequence and on longest isotactic propylene sequence. We developed a mathematical model to describe the CEF mechanism for ethylene/propylene copolymers over the entire compositional range using population balances for the crystallization and dissolution stages. The joint distribution of longest ethylene and isotactic propylene sequences determines how the copolymer populations crystallize and dissolve. The model was validated with experimental CEF profiles of ethylene/propylene copolymers varying from pure ethylene to propylene homopolymers.     

Facile synthesis of ethylene–propylene fully alternating copolymer and comparison with random copolymer of similar composition

A precisely sequenced ethylene–propylene (EP) fully alternating copolymer was synthesized via trans‐1,4‐polymerization of isoprene catalyzed by Ziegler–Natta catalyst followed by hydrogenation. This EP copolymer was used as model polymer for studying structure–property relationship. An ethylene–propylene random copolymer (ethylene–propylene rubber [EPR]) with similar ethylene content was also prepared for comparison, and the effect of comonomer sequence distribution on properties was investigated. The copolymer chain structures were monitored by ¹H and ¹³C NMR and Fourier translation infrared. Differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile tests were employed to determine the thermal and mechanical properties. The fully alternating copolymer EP gives a more precise glass transition comparing than EPR. Further understanding on thermal properties and aggregation behavior of ethylene–propylene copolymers is made possible by this comparative study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45816.     

PP/PE blends. IV. Characterization and compatibilization of blends of postconsumer resin with virgin PP and HDPE

The mechanical properties of blends of isotactic polypropylene and high-density polyethylene with a postconsumer resin (recycled dairy containers) were investigated over the entire composition range. Modification of these blends with an ethylene/propylene/diene copolymer or an ethylene/vinyl acetate copolymer was also investigated. Isotactic polypropylene/postconsumer resin blends have satisfactory impact and tensile properties at postconsumer resin contents of less than 50% for certain applications. At higher postconsumer resin contents, the tensile properties were adversely affected. The impact properties remained satisfactory. Addition of an ethylene/propylene/diene copolymer improved the mechanical properties of these blends to levels equal to or greater than those for neat isotactic polypropylene. Ethylene/vinyl acetate copolymers were also able to improve the mechanical properties, but not as efficiently as did the ethylene/propylene/diene copolymer. Blends of high-density polyethylene and a postconsumer resin had poor impact and tensile properties. Although the ethylene/propylene/diene copolymer and ethylene/vinyl acetate copolymers were able to improve these properties, the improvement was insufficient for general recycling, except at lower (≤25%) postconsumer resin contents. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2081–2095, 1998