双螺杆挤出机与反应性挤出加工技术

本文论述了双螺杆挤出机与反应性挤出加工技术的特点，介绍了其在聚合反应、聚合物可控降解、聚合物接枝及聚合物改性等方面的应用。     

平行双螺杆技术在改性双基推进剂产品研制中的应用

针对改性双基推进剂在单螺杆挤压工艺中易发生"倒料""打滑"等加工安全问题,在分析双螺杆技术特点及国内外关于火炸药研制、生产和综合应用的基础上,重点就平行双螺杆技术在某低黏度改性双基推进剂产品研制中的安全应用进行了研究,结果表明其综合工艺重现性较好。最后指出了双螺杆技术面临的主要问题,并提出了改进建议。     

双螺杆挤出机与反应性挤出加工技术

本文论述了双螺杆挤出机与反应性挤出加工技术的特点,介绍了其在聚合反应、聚合物可控降解、聚合物接枝及聚合物改性等方面的应用。     

浅析双螺杆挤出工艺在火炸药研制中的安全问题

综述了国外火炸药双螺杆挤出工艺安全技术发展状况,介绍了国内在双螺杆设备结构与承载力、新型火炸药产品研制、数值模拟技术应用等方面所做的安全改进工作,指出了与国外先进安全控制技术存在较大差距。重点分析了在火炸药基础研究、安全可加工性研究、双螺杆硬件设施与自动控制装置的完善,以及复合型人才培养等方面存在的问题,并提出了相应的解决措施。建议通过整合国内资源,加大资金投入和人才培养,有效促进国内火炸药双螺杆挤出工艺安全技术快速发展。     

双螺杆挤出生产PVC装饰板技术

文章介绍了PVC装饰板的生产工艺流程、模具配方、生产控制要点及装配。     

双螺杆挤出反应加工技术

反应加工技术已被用于塑料工业,可简化聚合工艺、进行聚合物改性以及聚合物的合金化。本文介绍了双螺杆挤出机的基本功能及用其进行反应加工的实例,还展望了这一技术的发展趋势。     

螺杆挤出技术加工火炸药的研究进展

从螺杆挤出技术加工火炸药的安全性分析、所加工物料类型以及物料性能改善三方面综述了火炸药螺杆挤出技术的研究进展,指出单螺杆挤出技术存在内摩擦力较高和双螺杆挤出技术建压不足等问题,说明了锥形双螺杆挤出机加工火炸药的适应性。     

双螺杆挤出过程中药料温度变化的影响因素

研究了在双螺杆挤出过程中,影响药料温度变化的有关因素,认为第一段机简 度是影响药温的显著因子,这些可以作为研究火药工艺温度的基础。     

泡沫胶料挤出用双螺杆挤出机

通常我们采用两台串联的单螺杆挤出机来完成聚脂和聚苯乙烯塑料泡沫的挤出,然而,最近由贝斯托大公司（Berstorffi研制开发的ZE/i联合双螺杆挤出机替代了一段混炼挤出机,且挤出效果相当好。     

Fluorescence monitoring of twin screw extrusion

An optical fiber probe has been constructed in order to obtain real-time measurements of fluorescence radiation during twin screw mixing and extrusion of plasticized polybutadiene and calcium carbonate particulate. The probe consists of an optical fiber bundle which was inserted along the axis of a half-inch sensor bolt, and it was used to transmit optical excitation energy to the processed material and to detect the subsequent fluorescence. The source of fluorescence radiation was a fluorescent dye which was doped into the processed ingredients at very low concentrations. Although most of our measurements were taken with the probe positioned close to the exit die, the sensor bolt can be placed in any instrumentation port along the extruder line. Experiments were carried out to measure residence time distribution, quality-of-mix, and mix concentrations as a function of processing conditions. Product mix changes in response to variations in material feed rates and screw RPM were also observed. Values of residence time were obtained by measuring the transit times for the dye to travel from an upstream injection port to the measurement probe, a distance of 63 cm. Flow instabilities, such as mat formation of the solids, were observed by noting the abrupt changes and discontinuities in the fluorescence signal.     

Simulation of intensity of segregation distributions using three-dimensional fem analysis: Application to corotating twin screw extrusion processing

The corotating twin screw extrusion flow is simulated to generate the distributions of intensity of segregation and integral measures of mixing and forwarding. The simulation focused on the lenticular kneading disk elements that necessitated the application of a three-dimensional finite element method to solve the conservation equations. The intensity of segregation distributions were determined by introducing a tracer blob numerically and tracking the concentration of the tracer particles as a function of location and time. In spite of the chaotic nature of the dynamics of this flow, the analyses provided the broad features of twin extrusion flow and its ability to mix. The processing characteristics of kneading disks were found to depend on the stagger angle and complemented earlier numerical and experimental results on residence time distributions and color incorporated tracer analyses. © 1995 John Wiley & Sons, Inc.     

Simulation of non-isothermal flow in modular co-rotating twin screw extrusion

Non-isothermal flow is simulated in the screw and kneading disc elements in a modular co-rotating twin screw extruder. Methods of calculating mean temperature rises for individual elements are discussed and results are presented. The implications of non-isothermal operation for scale-up is discussed. A method is then described for making calculations in a modular co-rotating machine, that contains many different elements. Example calculations are given showing the tendency of larger machines to buildup greater temperatures when viscous heating is included.     

Cook-off studies of propellants and explosives

A theoretical and an experimental study of the cook-off problem is proposed. The critical temperature for thermal explosion is analyzed as a function of the initial mass of propellant. A good agreement is found between theory and experiments.     

Ultrasound assisted twin screw extrusion of polymer-nanocomposites containing carbon nanotubes

The unique morphology and strong intertube attraction between carbon nanotubes (CNTs) make the dispersion of CNTs challenging and hence limit its effective use. A novel method for the continuous dispersion of multi-walled carbon nanotubes (MWNTs) in a polymer matrix for manufacturing high performance nanocomposites was developed using an ultrasonically assisted twin screw extrusion process. Reduction of the die pressure and variation of the ultrasonic power consumption as a function of amplitude were measured at various MWNT loadings. The effect of ultrasound on rheological, electrical, morphological and mechanical properties of polyetherimide (PEI) matrix and PEI-filled with 1-10 wt% MWNTs was studied. In the treated nanocomposites, the complex viscosity, storage and loss moduli were increased and damping characteristics were decreased as compared to untreated ones. Rheological and electrical percolations were found to be between 1 and 2 wt% MWNT loading. Ultrasonic treatment does not affect the electrical conductivity of nanocomposites. Mechanical properties such as Young's modulus and tensile strength were significantly increased with MWNT loading but moderately with ultrasonic treatment at high loadings and certain ultrasonic amplitudes. The morphology and state of dispersion of MWNTs were investigated by means of HRSEM. In the ultrasonically treated nanocomposites, the obtained micrographs showed excellent dispersion of MWNTs in PEI matrix.     

新型螺杆元件对LDPE-g-MAH反应挤出的影响

改变同向双螺杆挤出机主反应区的螺杆元件,研究该螺杆元件对低密度聚乙烯(LDPE)熔融接枝马来酸酐(MAH)的接枝产物和接枝率的影响。傅里叶变换红外光谱分析证实,部分MAH成功接枝到LDPE分子链上。对挤出沿程4个在线取样位置的试样做了对比分析,结果表明具有高剪切性能的捏合盘元件的沿程试样接枝率最大,熔体流动速率最小;具有高分布混合性能的齿形盘元件的沿程试样接枝率较大,熔体流动速率较小;具有回混作用的非啮合多过程元件能够迅速提高该元件所在区域的接枝率。     

同向双螺杆挤出机的共混技术

本文论述了聚合物共混须用同向双螺杆挤出机的原理、特征及不同物料的共混技术。     

Design features optimize twin screw plasticizing system for polypropylene extrusion

Work undertaken recently has looked at how the influence of a number of constructional features on the extruder of a twin-screw plasticizing system can affect the degree of polypropylene degradation in the process. Joachim Stasiek of Institute for Plastics Processing METALCHEM outlines the results of this research.