同向啮合双螺杆挤出机制备高性能环保再生橡胶及其性能研究

用同向啮合双螺杆挤出机对废旧轮胎全胎胶粉进行剪切脱硫,制备高性能环保再生橡胶,考察挤出工艺、补强树脂和软化剂的种类与用量对再生橡胶性能的影响。结果表明:挤出最佳工艺参数为机筒第1—13区温度为140/140/70/190/130/120/110/110/100/110/100/90/80℃,螺杆转速为140 r·min~(-1);与添加植物系软化剂的再生橡胶相比,添加矿物系软化剂固体无味油的再生橡胶物理性能更好;添加4份古马隆树脂作为补强剂,10份固体无味油作为软化剂,制备的再生橡胶物理性能最好。     

双螺杆挤出机胶粉脱硫工艺条件的研究

研究同向双螺杆挤出机的螺杆结构、脱硫温度和螺杆转速对胶粉脱硫的影响。结果表明：螺杆结构越有利于提高螺杆的混合和剪切能力，胶粉的溶胶含量越大，交联密度越小；当脱硫温度从170 ℃升高至190 ℃时，胶粉的脱硫效果有一定改善；当螺杆转速从50 r·min^-1增至90 r·min^-1时，胶粉的脱硫效果明显改善；当脱硫温度为180～190 ℃、螺杆转速为50～70 r·min^-1时，中等混合和剪切能力螺杆的脱硫胶粉的脱硫效果较好，胶粉胶料的拉伸性能较优。     

在双螺杆挤出机上连续混炼粉末橡胶

对于双螺杆挤出机上开发连续混炼工艺来说重要的是选择最好的螺杆组件，在本项开发工作中对不同的分散混炼组件进行了比较。本文还图示了其它参数，诸如喂料速度，螺杆速度，口型处形成的压力等对混炼工艺的影响。在此开发粉末橡胶连续混炼工艺的目标所追求的是获得良好的填充剂分散度和低混炼温度，以防止橡胶混炼胶焦炉。     

同向旋转双螺杆挤出机的连续混炼和脱硫工艺

对比了传统分批混炼和用同向旋转双螺杆挤出机连续混炼的方法。用同向旋转双螺杆挤出机连续混炼胶料,是传统分批混炼工艺的可行替代方法。混炼胶的组成和性能稳定,使产品质量更加稳定,同时大幅度简化了工艺,提高了自动化水平。利用同向旋转双螺杆挤出机还开发了新的橡胶脱硫工艺。用多种用途的橡胶进行了试验,材料性能测试结果表明,这种工艺方法极具应用前景。     

用同向旋转双螺杆挤出机实验研究橡胶混炼工艺

橡胶胶料的传统生产方法是在密炼机中将高粘度聚合物与填料和防老剂、硫化剂等其他助剂以间歇的方式进行混炼。而在双螺杆挤出机的连续混炼过程中,填料的混入和分散,以及其他助剂的分布等混炼过程是沿挤出机轴向完成的。该文采用天然橡胶（NR）及乳聚丁苯橡胶（E-SBR）与炭黑和白炭黑的橡胶-填料复合材料（RFC）实验研究了多工艺参数,即螺杆结构、螺杆转速及生产速度对胶料和产品性能的影响。结果表明,用连续工艺混炼的胶料,其性能与不连续混炼胶料的相当。     

用双螺杆挤出机制备聚琥珀酰亚胺的绿色合成工艺研究

以顺丁烯二酸酐和碳酸铵作为聚合原料,采用双螺杆挤出机作为聚合反应器制备了聚琥珀酰亚胺产品,研究了催化剂、反应温度、物料配比和螺杆转速对反应的影响。用FT-IR对其进行了结构表征,并用极限粘度法测定了聚琥珀酰亚胺的聚合度。结果表明,最佳合成条件为n(顺酐)∶n(碳酸铵)∶n(催化剂)=1∶1.5∶0.07,聚合温度为180、195、210℃,螺杆转速为60 r/min。该条件下的聚琥珀酰亚胺的聚合度可以达到276,单体转化率为91.6%。方法原料易得、操作简单、条件温和、无污染,为聚琥珀酰亚胺提供了一条绿色的合成方法。     

超大长径比双螺杆挤出机制备聚丙烯腈初生纤维

采用自主研发的超大长径比(136)双螺杆挤出机实现了PAN初生纤维的纺丝制备,研究了PAN粉料质量分数(16％、20％、24％)、双螺杆挤出机机筒温度(50、60、70 ℃)、循环挤出次数(0、1、2)对PAN初生纤维力学性能及表面形貌的影响.结果表明,PAN初生纤维的拉伸强度随质量分数、机筒温度和循环挤出次数的增加而...     

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。     

啮合同向双螺杆挤出过程中停留时间的模拟研究

修正了啮合同向双螺杆挤出机中的聚苯乙烯停留时间分布的一维模拟模型。对于输送单元通过C形腔内流体的本构方程推导速度分布，进而得到停留时间分布；引入Carreau—Yasuda模型来描述熔体黏度。在捏合块单元引入轴向分散模型描述该单元的停留时间分布。通过局部停留时间分布模型的修正改进了对双螺杆挤出机全局停留时间分布的预测。模拟研究了螺杆转速及喂料速率对停留时间分布的影响。模拟结果的峰形、最小停留时间、平均停留时间与实验测量相符合。     

同向双螺杆挤出楠的生产技术现状

本文从螺杆结构,传动系统、产量等方面比较了国内外同向双螺杆挤出生产技术现状并对市场和发展趋势作出了简介。     

用双螺杆挤出机制备丁腈橡胶/尼龙12热塑性弹性体

采用双螺杆挤出机通过动态硫化法制备了丁腈橡胶/尼龙12热塑性弹性体,考察了双螺杆挤出机的螺杆转速和机筒温度对所制备热塑性弹性体力学性能和微观形态的影响。结果表明,用双螺杆挤出机动态硫化制备的丁腈橡胶/尼龙12热塑性弹性体呈两相"海岛结构",即丁腈橡胶为分散相、尼龙12为连续相。随着挤出机螺杆转速的提高,弹性体的硬度、拉伸强度和扯断伸长率先增大后减小,撕裂强度和压缩永久变形逐渐降低;螺杆转速对弹性体耐油性能的影响不大;当螺杆转速增至400 r/min时,丁腈橡胶的粒径较小且分布均匀。随着双螺杆挤出机温度的升高,弹性体的硬度和拉伸强度逐渐增大,扯断伸长率、撕裂强度和压缩永久变形均先增大而后减小,耐油性能变差;温度升高使得丁腈橡胶难于在剪切作用下破碎,颗粒变大且分布不均。     

Melt-mixing by novel pitched-tip kneading disks in a co-rotating twin-screw extruder

Melt-mixing in twin-screw extruders is a key process in the development of polymer composites. Quantifying the mixing performance of kneading elements based on their internal physical processes is a challenging problem. We discuss melt-mixing by novel kneading elements called “pitched-tip kneading disk (ptKD)”. The disk-stagger angle and tip angle are the main geometric parameters of the ptKDs. We investigated four typical arrangements of the ptKDs, which are forward and backward disk-staggers combined with forward and backward tips. Numerical simulations under a certain feed rate and screw revolution speed were performed, and the mixing process was investigated using Lagrangian statistics. It was found that the four types had different mixing characteristics, and their mixing processes were explained by the coupling effect of drag flow with the disk staggering and pitched-tip and pressure flows, which are controlled by operational conditions. The use of a pitched-tip effectively controls the balance of the pressurization and mixing ability.     

The self-wiping co-rotating twin-screw extruder as a polymerization reactor for methacrylates

The self-wiping co-rotating twin-screw extruder was studied as a reactor for two polymerizations in bulk: the homopolymerization of n-butylmethacrylate and the copolymerization of n-butylmethacrylate with 2-hydroxypropylmethacrylate. The influence of the extrusion parameters on the product was analyzed. With both reactions, conversions up to 95% were obtained. Nevertheless, a significant difference was observed in the working domain of both polymerizations, in which a stable reactive extrusion process could be attained wherein the discharge rate is constant and equals the feed rate. In the case of the relatively fast copolymerization, both the throughput and the screw rotation rate could be raised without endangering the stability of the process. This was not the case for the homopolymerization studied. It was determined that the stability of the process depends on the reaction velocity and the product viscosity. Within the boundaries of the working domain, the molecular weight could be influenced by adjustments of the extrusion parameters.     

Screw optimization of a co-rotating twin-screw extruder for a binary immiscible blend

The effect of the screw configuration of a closely intermeshing co-rotating twin-screw extruder on residence time and mixing efficiency was studied for an uncompatibilized immiscible PA6/PP (80:20) bend. Alternative screw configurations were investigated systematically. The residence time distribution (RTD) was found to be a poor indicator of the total mixing efficiency, whereas the mixing intensity function yielded considerably better information. High shear stress, sufficient residence time, and high fill ratio in the melting section of the screw were the most important factors in achieving good dispersion of the minor phase. The evolution of morphology along the screw axis depended strongly on the screw configuration. The downstream flow characteristics after the screw end determined the final morphology of the blend.     

Morphology development of in situ compatibilized semicrystalline polymer blends in a co-rotating twin-screw extruder

This paper concerns the morphology development of in situ compatibilized semicrystalline polymer blends in a co-rotating, intermeshing twin-screw extruder, using polypropylene (PP) and polyamide 6 (PA-6) blends as model systems. The morphology of in situ compatibilized blends develops much faster that of mechanical ones. The size of the dispersed phase (PA-6) undergoes a 10⁴ fold reduction from a few millimeters to sub-micron during its phase transition from solid pellets to a viscoelastic fluid. The final morphology is reached as soon as the phase transition is completed, which usually requires only a small fraction of the screw length in a co-rotating twin screw extruder. Screw profiles and processing conditions (screw speed, throughput and barrel temperature) control the PA-6's melting location and/or rate, but do not have significant impact on the ultimate morphology and mechanical properties of in situ compatibilized blends. The finding that morphology of PP/PA-6 reactive blend develops rapidly makes it possible to produce compatibilized PP/PA-6 blends by the so-called one-step reactive extrusion. It integrates the traditionally separated free radical grafting of maleic anhydride onto PP and the compatibilization of PP/PA-6 into a single extrusion step.     

Measurement of three-dimensional velocity field in the translational region of a co-rotating twin-screw extruder

The velocity field in the screw channels of a co-rotating twin-screw extruder was measured using laser Doppler anemometry. Velocity distributions were measured for two screw elements having pitches of 14 and 28 mm, respectively. The magnitude of radial velocity component for both elements was no more than 10% of the magnitude of total velocity. The radial and the axial velocity components were similar for both screw elements. Wider range of tangential velocity values and steeper gradients near the flights were observed for smaller pitch screw element.     

同向双螺杆挤出机的停留时间分布及填充度

引 言 双螺杆挤出机在高分子材料加工中已被广泛地应用于聚合物共混改性、反应挤出及高分子可控降解等各个方面[1].但先前对挤出过程研究较少,一般仅停留在"黑箱"型经验操作的层面,主要以定性的机械设计为主.     

Resin distribution along axial and circumferential directions of self-wiping co-rotating parallel twin-screw extruder

A self-wiping co-rotating twin-screw extruder (TSE) is operated in a starved state in which the screws are partially filled with resin. Understanding the resin distribution on the screw surface of a TSE in this state is essential for the design, operation, and maintenance of the twin-screw extrusion process. Accordingly, in this study, the circumferential and axial distribution of resin in a TSE were simulated using a novel method combining the mathematical formulation of Hele–Shaw flow, the finite element method, and a newly developed down-wind pressure updating scheme. The results of the simulation were found to be in good agreement with experimental measurements. The proposed simulation method enables the detailed visualization of resin distribution in the entire axial and circumferential directions over the length of a TSE, improving the ability to determine both the devolatilization and fiber attrition during the extrusion process.     

白炭黑填充橡胶在双螺杆挤出机中的连续混炼

介绍了白炭黑填充橡胶胶料的技术发展现状,研究了硅烷化反应和双螺杆挤出工艺的主要参数的相关性。结果表明,白炭黑填充橡胶在同向旋转螺杆挤出机中连续混炼是可以实现的,剪切变形较高的螺杆构造,其Panye效应更低,硅烷化级别就更高;通过进一步优化过程和落实除气系统有可能获得与密炼机系统相近的硅烷化级别。