浅谈农用功能性棚膜

本文介绍了用于日光温室，塑料大棚和春季拱棚等塑棚温室覆盖的农业用聚乙烯吹塑棚膜的理想化状态，以及近几年来我国研制开发生产的聚乙烯耐老化棚膜、耐老化无滴双重覆盖功能吹塑棚膜，并详细介绍了具有多层我种覆盖功能的农业用聚乙烯吹塑棚膜。     

聚乙烯吹塑薄膜缺陷分析及对策

根据包装用聚乙烯吹塑薄膜国标要求,从原料、设备和工艺等方面分析了聚乙烯吹塑薄膜成型过程中影响产品质量的因素,对吹塑薄膜生产过程中常见的质量问题及产生缺陷的原因进行了分析,并给出了解决的措施。     

PE-UHMW挤出中空吹塑设备与工艺的研究

改型设计了改性超高相对分子质量聚乙烯的挤出中空吹塑设备，设计采用了专用的挤出螺杆、机筒、模头和模具，并研究改进了吹塑工艺及生产方法，从而克服了超高相对分子质量聚乙烯的加工难点，得到了合格的吹塑制品。     

聚乙烯吹塑薄膜质量控制分析

根据化工和包装用聚乙烯吹塑薄膜国标要求,从原材料、大型机械设备和施工工艺等方面分析了聚乙烯吹塑薄膜成型过程中影响产品质量的因素,常见问题如薄膜出现褶皱、鱼眼多、卷绕时跑卷、薄膜透明度差、薄膜厚度不均等,对吹塑薄膜生产过程中常见的质量问题及产生缺陷的原因进行了分析,并总结出了相应的解决办法和措施。     

影响PE吹塑薄膜质量因素的研究

本文从聚乙烯原料和主要添加剂的选用、主要加工参数的控制等方面对影响聚乙烯吹塑薄膜质量的因素进行了分析。影响聚乙烯吹塑薄膜质量的主要因素有：原材料和各类添加剂（如抗静电剂等）的选择、加工工艺条件（加工温度、挤出速度、吹胀比等）的控制等。     

添加剂对聚乙烯吹塑薄膜质量的影响

影响聚乙烯吹塑薄膜质量的主要因素有:原材料和各类添加剂(如抗静电剂等)的选择、加工工艺条件(加工温度、挤出速度、吹胀比等)的控制等。主要分析了添加剂对聚乙烯吹塑薄膜质量的影响。     

中空吹塑用PP专用树脂的流变性能和力学性能

采用熔体拉伸流变仪、动态旋转流变仪和力学性能测试仪对中空吹塑用聚丙烯专用树脂的流变性能和力学性能进行测试和表征,并对该树脂吹瓶应用效果进行了评价。结果表明:该中空吹塑用聚丙烯专用树脂可以达到吹瓶应用的各项性能要求,吹瓶成型合格率达到100%,成型后的单瓶瓶重相比聚乙烯可以减少5%~8%,达到了替代聚乙烯中空吹塑专用料水平。     

包装用聚乙烯吹塑薄膜拉伸强度的不确定度评定

以包装用聚乙烯吹塑薄膜拉伸强度的不确定度评定为例,分析了拉伸强度试验过程的不确定度来源,介绍了包装用聚乙烯吹塑薄膜拉伸强度不确定度的分析和计算方法.研究表明,试样宽度的测量对测量结果的不确定度贡献较大.     

独山子石化铬系大型中空吹塑聚乙烯新产品

截止今年6月23日，独山子石化公司已累计生产铬系大型中空吹塑聚乙烯产品超过万吨，实现了新产品的规模化生产。独山子石化公司依托白有聚乙烯装置的铬系催化剂技术，聚合生产出高摩尔质量级的高密度聚乙烯，根据市场定位调整工艺及性能，联合中科院化学所共同进行科研攻关，从而开发出满足市场需求的大型中空吹塑级聚乙烯专用料，填补了中国石油的一项产品空白。     

国内最大地膜吹塑机组诞生

由广东金明塑胶设备有限公司设计制造的ＭＤ -３４００型制品幅宽３２００ｍｍ的地膜吹塑机组日前通过验收 ,该新型地膜机组可生产国内幅度最大的农用地膜制品。ＭＤ -３４００型地膜吹塑机组适应１００%线型低密度聚乙烯或线型低密度聚乙烯与低密度聚乙烯、高密度聚乙烯共混原料 ,生产幅宽最大为３２００ｍｍ、厚度为０．００５～０．００８ｍｍ的农用薄膜 ,生产能力不小于６０００ｋｇ／天 ,能耗仅为０．２８ｋＷ·ｈ／ｋｇ制品。国内最大地膜吹塑机组诞生     

Review of life cycle assessment on polyolefins and related materials

Abstract

Life cycle assessment (LCA) is a sustainability measurement tool that identifies the environmental impacts of a product. The uniqueness of the LCA lies in its methodology, which aggregates all environmental burdens throughout the product’s life cycle, providing many variables for optimisation of the product (or process). Having occupied a major market share, the environmental impacts associated with the manufacturing and disposal of polyolefins are quite high. The main theme of this paper is to review the reported LCA studies on polyethylenes and polypropylenes including recycled plastics, biobased materials, which are competing with polyolefins, and polyolefin composites. The widely claimed green product ‘recycled plastic’ is analysed in detail from an LCA perspective, and key points, which determine its sustainability, are discussed. The environmental impacts associated with the manufacturing of polyolefins and their bioalternatives are highlighted. The few published studies of polyolefin composites on different applications are also discussed.     

IR transition moment orientational analysis on semi-crystalline polyethylene films

The recently developed approach of Transition Moment Orientation Analysis is employed to determine the three dimensional orientation and order of the different molecular moieties in semi-crystalline polyolefins. Based on IR transmission spectra for varying polarisation and inclination the quadratically averaged orientation distribution of the different IR transition moments is deduced. By that, the full order parameter tensor and its orientation with respect to the sample coordinate system is obtained.     

Fused Deposition Modeling of Polyolefins: Challenges and Opportunities

Polyolefins are the largest class of commercially available synthetic polymers that are extensively used in a variety of applications from commodities to engineering owing to their low cost of production, good physico-mechanical properties, light weight, good processability, and recyclability. Compared to conventional molding techniques, fused deposition modeling (FDM)-based 3D printing is a smart manufacturing technology for thermoplastics due to its low cost, ease of production of complex geometrical parts, rapid prototyping, and scalable customization. FDM 3D printing can be an ideal manufacturing technology for polyolefins to manufacture various complex parts. However, FDM 3D-printing of polyolefins is challenged bycritical printing problems like high warpage, dimensional inaccuracies, poor bed adhesion, and poor layer-to-layer adhesion. In this review, a fundamental understanding of polyolefins and their FDM 3D-printing process is established, and the recent progress of FDM 3D printing of polyolefins is summarized. Furthermore, strategies to overcome warpage and to improve mechanical strength of the 3D-printed polyolefins are provided. Finally, future prospectives of FDM 3D-printing of polyolefins are critically discussed to inspire prospective research in this field. It is believed that this review article can be tremendously useful for research work related to FDM of polyolefin-based materials.     

气相聚烯烃工艺进展

气相法生产LLDPE工艺的流程简单,投资和单耗低,环境问题少,综合衡量优于溶液法,淤浆法和高压法工艺。气相法PP工艺可在反应器内生产乙丙橡胶含量高的,高抗冲乙丙嵌段共聚物,可以直接从反应器生产分子量分布窄的具有超高熔体流动速率的牌号,是今后PP工艺的发展方向。文章介绍了UCC和BP气相LLDPE工艺及BASF、UCC/SHELL、Amoco的气相PP工艺进展。也讨论了制备乙丙嵌段共聚物的Spheripol工艺技术。     

聚烯烃材料的粘接技术

简要介绍了目前对聚烯烃材料进行良好粘接所采用的主要技术及应用范围比较广泛的胶粘剂     

Synthesis and reactive blending of amine and anhydride end-functional polyolefins

Polyolefins having low polydispersity and containing terminal functional groups are difficult to synthesize, due to limitations in catalysis technology. We have developed methods for preparing model polyolefins with terminal amine or anhydride functionality and of controlled molecular weight and narrow polydispersity. Both 1,4- or 1,2-polybutadienes are prepared by living anionic polymerization, with introduction of a functional group precursor during chain termination. The functional groups are protected as tert-butyl carbamate and tert-butyl ester for the amine and anhydride, respectively. The polymers are hydrogenated heterogeneously, with subsequent deprotection yielding saturated polymers with functionalities of up to 90%. These materials, due to their low polydispersity, comprise a useful model system for measuring melt reaction kinetics by gel permeation chromatography. Melt blending of amine- and anhydride-functional PEE90 (polyethylethylene) with complementary functional polystyrenes quickly yields extensive amounts of block copolymer with complex, sub-micron scale morphologies. Similar fine morphologies are observed for blends of amine- and anhydride-functional PE (polyethylene) with functional polystyrene. These functional PE and PEE90 polymers can also be used as reactive compatibilizers for polyethylene and polypropylene blends, respectively. The concentration of compatibilizer required to obtain sub-micron particles, however, is as high as 20% by weight.     

亲水性聚烯烃纤维的改性方法研究进展

聚烯烃以其优异的性能、低廉的价格和越来越广泛的用途,日益成为一种重要的合成高分子材料的主体。但它极弱的亲水性限制了在一些领域的应用。介绍了近几年国内外通过化学接枝、等离子体接枝、辐射接枝、表面光接枝等方法对聚烯烃表面亲水性改性的研究进展。     

Reprocessable and Recyclable Crosslinked Polyethylene with Triple Shape Memory Effect

Thermosetting polymers, such as epoxy resins, have found widespread applications because of their excellent thermomechanical and solvent resistance properties. However, the recycling of thermosets remains a challenge, due to the irreversible covalent crosslinking bonds in the network. The exchangeable covalent bonds in vitrimers open opportunities in the way that materials can be dynamically repaired. However, in the case of polyolefins, the strategy of exchangeable vitrimers is still underexplored. Herein, a simple way is reported to prepare a high‐density polyethylene (HDPE) vitrimer with a triple shape memory effect, where exchangeable esters are introduced into the network of covalently crosslinked HDPE. With the incorporation of polyethers or polyesters into the crosslinked network, the two obtained vitrimers show outstanding recyclability and a good triple shape memory effect. This new strategy of preparing an HDPE vitrimer might allow the high‐value utilization of crosslinked polyolefins.     

CPP/AN/S接枝共聚物合成及粘接性能研究

用丙烯腈 (AN)、苯乙烯 (S)对氯化聚丙烯 (CPP)进行接枝共聚 ,考察了不同条件下制得的CPP/AN/S接枝共聚物胶粘剂对聚烯烃材料的粘接性能 ,结果表明CPP/AN/S共聚物胶粘剂对聚烯烃材料具有较好的粘接性能。     

An overview of degradable and biodegradable polyolefins

The use of engineering plastics, especially polyolefins has increased significantly in recent decades largely due to their low cost, good mechanical properties and light weight. However, this increase in usage has also created many challenges associated with disposal and their impact on the environment. This is because polyolefins do not easily degrade in the natural environment and hence the need for degradable polyolefins has become a major topic of research. Degradable polyolefins are designed to retain functionality as a commodity plastic for the required service life but degrade to non-toxic end products in a disposal environment. They are typically designed to oxo-degrade while undergoing changes in chemical structure as a result of oxidation in air, thus causing the breakdown of the molecules into small fragments that are then bioassimilated. This article presents (i) a comprehensive review of the chemistry of additives for the degradation of polyolefins, (ii) a patent and scientific literature summary of technologies including commercially available systems, (iii) the mechanisms of degradation and biodegradation, (iv) testing methods and (v) toxicity.