超高分子量聚乙烯的特性及应用进展

超高分子量聚乙烯性能卓越、加工困难,是一种正在迅速崛起的工程性热塑性塑料。由于加工困难．国内外超高分子量聚乙烯的应用多集中在压制产品上,但是材料学家们从来没有停止过对超高分子量聚乙烯挤出制品的探讨。超高分子量聚乙烯的卓越性能源自于它具有极高的分子量,因此对超高分子量聚乙烯改性成功与否的判定在很大程度上取决于其制品的分子量保留的程度和在低温下的冲击韧性。作者利用新的挤出理念,精确的配方和精湛的工艺成功的挤出了分子量在250万以上的超高分子量聚乙烯管材制品,并对超高分子量聚乙烯的纤维、膜制品的应用进行了概要的介绍。     

双柱塞超高分子量聚乙烯特殊挤出成型工艺研究

介绍了超高分子量聚乙烯的熔体特性,如粘度极高、熔体指数几乎为零、摩擦因数小、临界剪切速率低等,给成型加工带来了很大的困难。针对其特殊性采取特殊的挤出成型工艺(复合挤出、双柱塞式挤出)。挤出时脉动小、加热快,并且可以挤出分子量不同纯超高分子量聚乙烯制品。     

UHMWPE的近熔点挤出技术及制品性能与应用

概述超高分子量聚乙烯(UHMWPE)材料改性和加工技术的进展,提出了近熔点挤出的理念,着重介绍了江苏联冠科技发展有限公司推出的分子量在250万以上的UHMWPE挤出制品的生产新技术及其制品性能检测结果,展望了UHMWPE管材的应用领域。     

超高分子量聚乙烯的改性及其应用

综述了超高分子量聚乙烯的改性进展,研究了层状硅酸盐对超高分子量聚乙烯加工及理化性能的影响。     

大口径超高分子量聚乙烯（UHMW—PE）管材的研制

本文介绍了超高分子量聚乙烯加工技术与设备的最新进展,采用ＳＴＪ系列柱塞推压（挤出机生产大口径薄壁超高分子量聚乙烯管材的特点与优势以及超高分子量聚乙烯管材的应用前景。     

超高分子量聚乙烯滤板的成型工艺

介绍采用烧结压铸法生产大型超高分子量聚乙烯压滤机滤板的成型工艺，着重叙述了模具设计，加工工艺以及填料和工艺条件对制品性能的影响。     

我国超高分子量聚乙烯行业发展现状及前景

超高分子量聚乙烯纤维是第三代高性能纤维。本文从市场、生产和加工工艺技术角度对我国超高分子量聚乙烯行业发展现状进行了分析,并对我国"十二五"期间超高分子量聚乙烯行业的发展前景进行预测。     

超高分子量聚乙烯的成型工艺及改性研究进展

本文介绍了超高分子量聚乙烯材料的基本性能,并由其性能决定的成型工艺,由于超高分子量聚乙烯熔体粘度极高,加工比较困难,限制了其的应用;通过综述近年来的超高分子量聚乙烯的改性研究进展,认为只有进行有力的改性研究,才可以将超高分子量聚乙烯的优异性能得到更为广泛研究和应用。     

超高分子量聚乙烯材料注塑工艺参数的优化

超高分子量聚乙烯(UHMWPE)具有优异的物理和力学性能,应用领域广阔,是一种可取代金属材料的高性能工程塑料。通过近年来对超高分子量聚乙烯的研究,超高分子量聚乙烯只有经过改性,才能提升其功能性,拓展其应用领域。基于正交实验设计原理,采用L_(16)(4~5)正交表进行试验,在超高分子量聚乙烯注塑成型过程中,研究了工艺参数对样条制品承受最大拉力性能的影响。实验结果表明,在选定的范围内,相对于其他工艺参数而言,注射压力对超高分子量聚乙烯注塑成型样条制品承受的最大拉力作用明显,属于显著影响因素。最佳工艺组合为注射压力90MPa,计量段温度275℃,注射速度60 mm/s,螺杆转速60 r/min,百分比为30%。     

超高分子量聚乙烯（UHMW－PE）制品单螺杆连续挤出成型工艺技术

超高分子量聚乙烯（ＵＨＭＷ－ＰＥ）制品单螺杆连续挤出成型工艺技术超高分子量聚乙烯（ＵＨＭＷ－ＰＥ）通常指粘均分子量在１５０万以上，重均分子量在３０（）万以上的线型聚乙烯，分子结构虽与普通聚乙烯完全相同，其物理机械。注能却远远超过了普通聚乙烯，成为一种...     

UHMWPE结晶形态对冲击性能的影响

了超高分子量聚乙烯结晶形态对冲击性能的影响，模压烧结法制样，发现不同工艺条件制备的ＵＨＭＷ－ＰＥ制品的结晶形态差别很大，从而导致材料的抗冲击也截然不同，制品冲击强度取决于结晶度，晶体结构形态，工艺条件控制ＵＨＭＷＰＥ结晶形态为直径较粗大的类串晶形态，有利于提高制品的冲击性能。     

Structure of ultrahigh molecular weight polyethylene–air counterflow flame

The combustion of ultrahigh molecular weight polyethylene (UHMWPE) in airflow perpendicular to the polyethylene surface (counterflow flame) was studied in detail. The burning rate of pressed samples of UHMWPE was measured. The structure of the UHMWPE–air counterflow flame was first determined by mass spectrometric sampling taking into account heavy products. The composition of the main pyrolysis products was investigated by mass spectrometry, and the composition of heavy hydrocarbons (C₇—C₂₅) in products sampled from the flame at a distance of 0.8 mm from the UHMWPE surface was analyzed by gas-liquid chromatography mass-spectrometry. The temperature and concentration profiles of eight species (N₂, O₂, CO₂, CO, H₂O, C₃H₆, C₄H₆, and C₆H₆) and a hypothetical species with an average molecular weight of 258.7 g/mol, which simulates more than 50 C₇—C₂₅ hydrocarbons were measured. The structure of the diffusion flame of the model mixture of decomposition products of UHMWPE in air counterflow was simulated using the OPPDIF code from the CHEMKIN II software package. The simulation results are in good agreement with experimental data on combustion of UHMWPE.     

UHMWPE制品的受热形变和热变形加工

分析了分子量，加工助剂和无机填料对ＵＨＭＷＰＥ熔点的影响，论述了ＵＨＭＷＰＥ制品在受热过程中尺寸变化规律，及热收缩率与制品热历史的关系和无机填料对收缩率的影响，提出了ＵＨＭＷＰＥ制品由形简单变为形状复杂制品的热形加工方法，并实现了两种形状复杂制品的热变形加工。     

超高分子量聚乙烯材料的研究进展

超高分子量聚乙烯（UHMWPE）是高性能聚烯烃材料的典型代表,稳定的线性长链结构使其具有高强度、耐冲击、耐磨损、自润滑、耐化学腐蚀、耐低温等诸多优异性能。近年,UHMWPE加工、改性技术日益扩展、优化,形成了多种多样的UHMWPE制品,广泛应用于军民各项领域。本文综述了UHMWPE在催化聚合、纤维、膜、管材、板材及型材等方面的最新进展,重点介绍在各领域应用、加工、改性等方面的研究成果和发展趋势。     

Effect of gamma ray irradiation on processability and properties of ultra high molecular weight polyethylene

Ultra high molecular weight polyethylene (UHMWPE) has been widely used in many fields due to its outstanding properties. However, it is virtually impossible to be processed by the conventional method due to its high molecular weight and very tight chain entanglement. To solve this problem, a new method was proposed in this article. Gamma ray irradiation was adopted to cause the oxidation degradation of UHMWPE. The degraded products which generated in situ and dispersed in UHMWPE evenly were utilized as self‐lubricant and heat transfer intermediary. These low molecular weight fractions thus could improve the processability of UHMWPE. The effects of irradiation dose on the structure and properties of UHMWPE were studied by fourier transform infrared (FTIR) spectroscopy, gel content measurement, wide angle x‐ray diffraction (WAXD), Haake torque rheometer, mechanical properties measurements and sliding wear tests. The experimental results showed that gamma ray irradiation caused oxidation degradation of UHMWPE. Under appropriate irradiation condition, the processability of UHMWPE could be improved substantially while most of its excellent properties could be kept. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Reducing the flammability of ultra-high-molecular-weight polyethylene by triphenyl phosphate additives

The thermal degradation and combustion of ultra-high-molecular-weight polyethylene (UHMWPE) doped with triphenyl phosphate (TPP) at atmospheric pressure was studied by molecular beam mass spectrometry, dynamic mass spectrometric thermal analysis, microthermocouples, thermogravimetry, gas chromatography/mass spectrometry. The kinetics of thermal degradation of pure UHMWPE and that mixed with TPP at high (≈150 K/s) and low (0.17 K/s) heating rates was investigated. The effective values of the rate constant and activation energy of the thermal degradation reaction were determined. Burning velocity and temperature profiles in UHMWPE and UHMWPE + TPP flames were measured. The composition of the combustion products in a flame zone adjacent to the burning surface of the sample was determined. TPP vapor in the flame was detected. The addition of TPP to UHMWPE was found to reduce the flammability of the polymer. It is shown that TPP acts as a fire retardant in both the condensed and gas phases.     

Rheological and mechanical properties of blends of LDPE with high contents of UHMWPE wastes

The mixing of UHMWPE wastes with other polymers aims to reduce the environmental impact of waste materials. The dynamic rheological behavior of the blends, tensile and abrasion properties, Shore D hardness and impact resistance, and morphology are important in characterizing polymer blends. In this work, we have sought to obtain blends containing different proportions of UHMWPE wastes and LDPE with properties suitable for the manufacture of useful products. The blends exhibit an increase in complex viscosities, storage modulus, and Young's modulus with increasing content of UHMWPE wastes and a decrease in both the maximal elongation and Charpy impact resistance. Summarizing, the addition of up to 60 wt % of industrial fragments of UHMWPE is possible using conventional methods of processing to prepare blends with values of tensile strength, abrasion, and Shore D hardness similar to those of LDPE. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44996.     

分子量200万以上UHMWPE双抗挤出制品的开发

用分子量380万的超高分子量聚乙烯(UHMWPE)树脂为基体树脂,加入高含量导电炭黑/聚乙烯蜡复合导电剂,溴-锑系与膨胀型阻燃剂组成的复配阻燃荆及常规挤出加工助剂,利用近熔点挤出理念及其加工设备,实现了分种子量200万以上UHMWPE管材、板材制品的连续挤出.制品综合性能超过了2005年国家煤炭行业的技术标准,对提高行业技术水平、解决现实煤炭生产中的安全隐患、促进UHMWPE上下游产业的发展做出了贡献.     

The effects of hybrid fillers on thermal,mechanical, physical,and antimicrobial properties of ultrahigh‐molecular‐weight polyethylene‐reinforced composites

The effects of hybrid filler of zinc oxide and chitosan (chitosan–ZnO) on thermal, flexural, antimicrobial, chemical resistance, and hardness properties of ultrahigh‐molecular‐weight polyethylene (UHMWPE) composites with varying concentration of zinc oxide (ZnO) and further hybridized by chitosan (CS) were successfully studied. The composites were prepared using mechanical ball milling and followed by hot compression molding. The addition of ZnO to the UHMWPE matrix had lowered the melting temperature (T _m) of the composite but delayed its degradation temperature. Further investigation of dual filler incorporation was done by the addition of chitosan to the UHMWPE/ZnO composite and resulted in the reduction of UHMWPE crystallization. The flexural strength and modulus had a notably high improvement through ZnO addition up to 25 wt% as compared to neat UHMWPE. However, the addition of chitosan had resulted in lower flexural strength than that of 12 wt% ZnO UHMWPE composite but still higher than that of neat UHMWPE. It was experimentally proven that the incorporation of ZnO and chitosan particles within UHMWPE matrix had further enhanced the antimicrobial properties of neat UHMWPE. Chemical resistance was improved with higher ZnO content with a slight reduction of mass change after the incorporation of chitosan. The hardness value increased with ZnO addition but higher incorporation of chitosan had lowered the hardness value. These findings have significant implications for the commercial application of UHMWPE based products. It appears that these hybrid fillers (chitosan–ZnO)‐reinforced UHMWPE composites exhibit superior overall properties than that of conventional neat UHMWPE. POLYM. COMPOS., 38:1689–1697, 2017. © 2015 Society of Plastics Engineers