硬聚氯乙烯低发泡挤出成型研究

采用自由发泡挤出的方法研究了硬聚氯乙烯低发泡挤出成型的配方设计和工艺条件控制。讨论了稳定剂品种，改性剂品种和发泡剂用量对制品密度，泡孔结构以及外观表面的影响。还揭示了口模温度和螺杆转速与制品密度的关系。     

影响PVC挤出制品发泡质量的因素

阐述了ＰＶＣ挤出发泡制品的发泡原理,分析了在挤出过程中配方、工艺对产品发泡质量的影响。     

PVC/木粉复合材料挤出发泡成型的研究

介绍木塑复合材料挤出发泡成型的发展和加工难点,针对聚氯乙烯(PVC)／木粉复合材料挤出发泡的成型方法,从原料、配方、工艺、设备等方面作了详细分析。简述了PVC／木粉复合材料挤出发泡制品的性能及影响制品性能的主要因素。     

发泡聚丙烯型材的挤出研究

研究了低发泡聚丙烯（PP）配方中各种成分对制品质量性能的影响，并通过正交设计实验筛选出最佳配方。同时讨论了单螺杆挤出机的挤出工艺条件对发泡制品性能的影响并确定了最佳工艺条件。     

PVC／木粉复合材料挤出发泡成型的研究

介绍木塑复合材料挤出发泡成型的发展和加工难点，并针对聚氯乙烯（PVC）／木粉复合材料挤出发泡的成型方法，从原料、配方、工艺、设备等方面作了详细分析。最后简述了PVC／木粉复合材料挤出发泡制品的性能及影响制品性能的主要因紊。     

影响U-PVC挤出制品表面亮度的因素分析

介绍了未增塑聚氯乙烯(U-PVC)制品的整个生产成型过程,从配方、加工工艺、挤出模具结构、水气冷却功效等各方面进行了分析,找出了影响制品表面亮度的各种因素。     

塑料异型材的挤出成型

概述塑料异型材的优点及应用实例，从原料选择与配方设计、挤出设备、制品断面设计及机头模具、挤出成型工艺等方面阐述了塑料异型材的挤出成型技术，介绍了低发泡、复合共挤出等其它异型材的成型技术，并展望了塑料异型材的发展趋势。     

塑料成型加工实用技术讲座(第七讲)塑料异型材的挤出成型

概述塑料异型材的优点及应用实例，从原料选择与配方设计、挤出设备、制品断面设计及机头模具、挤出成型工艺等方面阐述了塑料异型材的挤出成型技术，介绍了低发泡、复合共挤出等其它异型材的成型技术，并展望了塑料异型材的发展趋势。     

氯乙烯-丙烯酸丁酯共聚树脂在农业用PVC-U管材加工中的研究与应用

以氯乙烯-丙烯酸丁酯(VC-BA)作为一种节水农用PVC-U管材增韧改性剂,通过熔融共混的挤出加工工艺,制备了一定规格的农用PVC-U输水管试样。检测结果表明,与原配方比较,新配方体系的挤出加工性能得到了改善,融熔温度降低了5℃,塑化时间缩短,挤出效率提高了4.7%,管材制品的柔韧性、承压能力等指标得到显著提升。     

用粉料一步法挤出RPVC异型材配方及工艺探讨

本文针对用国产单螺杆挤出机粉料一步法挤出RPVC异型材的配方及工艺问题进行了探讨,发现SG—5、6型树脂在粉料状态下适于单螺杆挤出机的制品加工,其制品性能较好。一步法挤出RPVC异型室内装饰封条配方如下:PVC(SG5—6)100、DOP6、三盐基硫酸铅2、二盐基性亚磷酸铅1.5、硬脂酸铅0.2、硬脂酸钙0.6、ACR3、IU复合润滑剂1、MBS5(可不加)、轻质碳酸钙10、着色剂定量。     

Foam extrusion characteristics of thermoplastic resin with fluorocarbon blowing agent. III. Foam sheet extrusion of polystyrene and low-density polyethylene

An experimental study was conducted on the extrusion of polystyrene and low-density polyethylene foam sheets, using fluorocarbon blowing agents and a tubular die. The effects of the type and concentration of blowing agent, die temperature, and takeoff speed on foam extrusion characteristics were investigated. They are foam density, tensile modulus, and cell morphology. It has been found that die temperature greatly influences the open cell fraction and foam density and that the takeoff speed greatly influences cell orientation, which, in turn, has a profound influence on the tensile modulus of the foam sheets produced.     

Foam extrusion characteristics of thermoplastic resin with fluorocarbon blowing agent. I. Low-density polyethylene foam extrusion

An experimental study was conducted to investigate the foam extrusion characteristics of low-density polyethylene resin. For the study, we used dichlorotetrafluoroethane and dichlorodifluoromethane as blowing agent and talc as nucleating agent. In the study, we investigated the effects of processing and material variables on the foam extrusion characteristics, namely extrudate swell behavior, foam density, and cell morphology. It was found that an inverse relationship exists between the extrudate swell ratio and the foam density. Also investigated was the effect of die geometry (theL/D ratio, D_R/D ratio, and entrance angle) on the foam extrusion characteristics of low-density polyethylene resin. Suggestions are made on the experimental technique that may be useful in selecting resins for foam extrusion operation. Also suggested are guidelines for selecting an optimum die geometry that would produce good quality foams of low-density polyethylene.     

超临界CO2对聚乳酸挤出发泡的影响

采用一种半结晶聚乳酸（PLA）,利用双螺杆串联熔体泵系统,以超临界CO2为发泡剂,进行挤出发泡实验。研究了CO2含量对PLA泡沫密度、泡孔密度和泡孔直径的影响。结果表明,发泡剂CO2含量在7 %～10 %（质量分数,下同）之间时,得到表观密度最低为40 kg/m3、泡孔直径为285 μm、泡孔密度为1.5×106 个/cm3的低密度PLA泡沫。随着CO2含量的增加,PLA泡沫的初始结晶峰减小,结晶度升高,说明超临界CO2对PLA的结晶具有促进作用。     

Influence of different process and material parameters on chemical foaming of fluorinated ethylene propylene copolymers

In this article, the chemical foaming of fluorinated ethylene propylene copolymers (FEP) is investigated. For the laboratory scale foam extrusion process, a chemical blowing agent adapted to the high melting temperature of FEP had to be found. Foaming experiments were carried out varying process and material parameters. Foam densities as well as cellular structures were analyzed to characterize how the parameters influence the foaming behavior of the FEP melt. An increasing rate of the foam extrusion caused an augmentation of cell numbers at a simultaneous decrease of their diameters. Moreover, a pronounced reduction of the foam density with increasing output rate could be observed. Changing the temperature of the foam extrusion, an optimum in density reduction and homogeneity of the cell size was found. Furthermore, the influence of an appropriate nucleation agent on the resulting geometry and amount of cells was investigated. Though the chemical blowing agent itself can act as an implement for nucleating cell growth, an addition of 10 wt% of calcium fluoride particles showed a significant augmentation in cell quantity. For the chemical foam extrusion process, three FEP with different viscosities were characterized. With decreasing viscosity, a reduction in foam density could be observed for all temperatures. POLYM. ENG. SCI., 47:1740–1749, 2007. © 2007 Society of Plastics Engineers     

组合发泡剂对聚丙烯发泡行为的影响研究

采用物理发泡剂和化学发泡剂的组合发泡剂对聚丙烯(PP)和高熔体强度聚丙烯(HMSPP)在自制的单螺杆串联单螺杆挤出发泡机组上进行挤出发泡试验。通过真密度计/开闭孔率测定仪和扫描电子显微镜对发泡制品的密度、发泡倍率和泡孔形态进行测试。研究结果表明,采用组合发泡剂后,大部分PP和HMSPP发泡制品的泡孔密度提高,发泡倍率增加,泡孔尺寸分布更加均匀,泡体结构优于单独使用物理发泡剂或化学发泡剂的发泡制品。     

Physical Blowing Agent Residence Conditions Stimulated Morphological Transformations in Extrusion Foaming

In this study, influence of blowing agent residence conditions on foam attributes has been investigated in extrusion foaming process. The blowing agent injection location in the extrusion barrel was found to affect the residence time inside the barrel, which in turn significantly transformed the foam microstructure. The injection location providing higher gas residence time resulted in foams with lower cell size, higher expansion ratio, and enhanced cell density. Further studies were performed to analyze the synergistic influence of residence time variation on foam attributes at different screw rotational speeds, die temperatures, and blowing agent contents.     

Rigid cellular PVC—the next house siding material?

The technology for extruding rigid cellular PVC has grown substantially over the past decade. Formulation additives, tooling, and processing expertise have made possible a variety of applications—relatively complex profiles, foam-core pipe, thermoformable foam sheet, and house siding. In the U.S. market, vinyl house siding is typically a relatively thin extrusion that is folded into a final shape that resembles wood cladding in appearance. An alternative to conventional form vinyl siding could be a foam structure that is thicker and stiffer than the solid form, and with a density similar to that of wood. This paper presents several performance advantages of rigid cellular PVC cladding in comparison to the current solid product, in addition to mentioning certain limitations that exist in the foam product that is produced with the technology available today.     

低发泡聚氯乙烯结皮板材生产技术

分析了低发泡聚氯乙烯结皮板材的挤出生产技术。在低发泡聚氯乙烯结皮板材生产中,选用螺杆特性硬的双螺杆挤出机、无发泡死角的模头,选用聚合度700~800,K值55~68的PVC原料,以及复合型发泡剂,挤出温度控制在140~160℃,可以生产性能比较优异的制品。     

微孔塑料及其挤出成型技术

介绍微孔塑料及其挤出成型技术,并与一般挤出发泡成型进行了比较。     

Biodegradable foams of poly(lactic acid)/starch. II. Cellular structure and water resistance

Biodegradable foams were prepared with poly(lactic acid) and starch by extrusion. The compression modulus of the foams was negatively related to the foam bulk density. The foam consists of both open‐ and close‐cell structures. The presence of PLA significantly improved the water resistance of the foam, and significantly improved the foam recovery capacity, especially in high‐moisture conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007