国内外新型混炼装备的研究动向

结合新型混炼技术与装备的理论研究和开发实践,对国内外混炼技术的研究现状和发展趋势进行了述评.重点介绍了同向平行双螺杆挤出机、往复式销钉螺杆挤出机和串联式磨盘螺杆挤出机的结构特点、设计原理、混炼机理和应用领域.     

新型混炼技术应用研究

聚合物改性对混炼设备的性能提出了更高要求。介绍了自主研制的5种新型混炼设备：同向平行双螺杆挤出机、串联式磨盘螺杆挤出机、往复式销钉螺杆挤出机、新型销钉式冷嗖料橡胶混炼挤出机的性能特点、适用范围、结构机理等。并对几种设备的混炼效果作了重点介绍。     

混炼装备的研究现状与发展

本文对国内外混炼装备的研究现状和发展趋势进行了评述,详细地介绍了同向双螺杆混炼挤出机、FCM连续混炼机、往复式销钉螺杆挤出机等几种新型混炼设备,然后重点从混炼原理、设计原理及应用等方面对串联式磨盘螺杆挤出机进行了分析,最后对混炼技术与装置的发展趋势进行了展望,提出了几种混炼装置及技术的发展方向。     

混炼装备的研究现状和发展

本文对国内外混炼装备的研究现状和发展趋势进行了评述，详细地介绍了同向双螺杆混炼挤出机、FCM连续混炼机、往复式销钉螺杆挤出机等几种新型混炼设备，然后重点从混炼原理、设计原理及应用等方面对串联式磨盘螺杆挤出机进行了分析，最后对混炼技术与装置的发展趋势进行了展望，提出了几种混炼装置及技术的发展方向。     

高聚物成型加工技术与装备的研究现状及发展

介绍了高聚物加工技术、过程理论计算和装备的现状及发展,其中详述了高效多功能螺杆混炼机(同向平行双螺杆混炼挤出机、往复式销钉螺杆挤出机、串联式磨盘螺杆挤出机)、塑料特种挤出装备(塑料电磁动态塑化挤出机、手提式高速排气挤出机、熔体齿轮泵挤出机、异向旋转锥形双螺杆挤出机)及其发展趋势,并对此领域的发展提出了导向性建议。     

三螺杆动态混炼挤出机振动强化mEPDM增韧PP的研究

三螺杆动态混炼挤出机将振动力场引入到物料的塑化混炼挤出过程,达到强化混炼和分散的目的.从实验的角度研究了三螺杆动态混炼挤出机中央螺杆的轴向振动对mEPDM增韧PP的作用规律与机理.研究发现,振动力场强化了PP/mEPDM共混物的冲击韧性;mEPDM含量不同,振动对PP/mEPDM共混物冲击强度提高的幅度亦不相同;随着振动频率或振幅的提高,PP/mEPDM共混物的冲击强度表现出先增大后减小的趋势.     

WXJ-140往复式销钉螺杆挤出机的研究与开发

往复式销钉螺杆挤出机具有特殊的结构和运动形式,具备了压力低、剪切低、温升低和混炼质量高的加工特性,广泛应用于各种材料的加工。结合WXJ-140往复式销钉螺杆挤出机的研发实践经验,介绍了该机型螺杆的结构特点和设计方法,阐述了销钉的设计和布置原理,重点对新型四头螺纹混合元件的混合机理进行了研究。     

往复式销钉螺杆挤出机混合机理概述

结合研制实践 ,分析了往复式销钉螺杆挤出机挤压系统的特点 ,阐述了该类机型的混合机理 ,并与常规的单、双螺杆挤出机作了比较     

三螺杆动态混炼挤出HDPE／Mg（OH）2复合材料性能的研究

从实验的角度研究了三螺杆动态混炼挤出机中央螺杆的轴向振动对Mg(OH)2填充HDPE性能的影响规律与机理.结果表明,振动力场的引入增强了Mg(OH)2在HDPE中分散效果,提高了复合材料的拉伸性能和冲击性能,阻燃性能也得到了改善.     

销钉注塑螺杆对物料混合效果的研究

运用基于有限元的CFD分析软件POLYFLOW,对五种销钉注塑螺杆的计量段进行了三维瞬态模拟.五种销钉螺杆元件包括圆形销钉螺杆元件(两种排列方式)、方形销钉螺杆元件和菱形销钉螺杆元件(两种导程).列计算得到的压力场、速度场、剪切速率场等进行后处理,分析不同销钉螺杆元件在计量段对熔料的混合效果及销钉周围熔料滞留情况.     

销钉机筒挤出机螺槽横截面内流体流动与混合的研究

在一定简化条件下，对销钉机筒挤出机螺槽横截面内的流场及混合均化效果以及销钉位置对流场和混合均化效果的影响进行了数值与实验研究。提出了流场中某点混合均化效果、整个流场平均混合均化效果以及混合均化效果统计分布的数值计算与评价方法。数值分析结果与实验结果具有较好的一致性。结果表明，销钉对物料具有明显的强化流动与混合均化的作用：销钉愈接近于螺棱，强化混合均化的效果愈显著：有销钉结构较无销钉结构的平均混合均化效果提高2．5％-5．6％；有销钉结构随着挤出时间的增加，混合均化效果不断提高，无销钉结构随着挤出时间的增加，当混合均化效果达到一定值后则不再提高。     

振动作用下异向双螺杆螺槽内熔体行为

采用Tanner方法修正的非线性MaxweⅡ本构方程，对振动力场作用下的聚合物熔体在平行异向双螺杆挤出机螺槽内的行为与响应进行了近似解析研究。分析了不同幂律指数的聚合物熔体在螺槽内的速度分布及其对振动力场的响应。随着幂律指数减小，C型室中上部混合变差，但振动力场使速度场随时间周期性变化，促进了流体界面再取向，进而提高混合效果。     

销钉单螺杆混炼段分布混合性能的数值研究

用正交设计法设计了9组不同排布的销钉单螺杆。采用混合熵作为评价销钉单螺杆混炼段混合性能的指标,数值研究了不同销钉结构的单螺杆混炼段内聚丙烯熔体的等温流动过程,考察了一个导程内销钉排数、每排销钉个数和销钉高度对销钉单螺杆混炼段混合性能的影响。结果表明,在所设计的正交试验中,沿螺杆挤出方向各截面的混合熵逐渐增大,出口处该值达到最大;在销钉螺杆混炼段一个导程内安装5排,每排5个高度为12 mm的销钉时,其混合性能较优。     

振动力场下填充聚合物挤出过程研究

研究了利用塑料电磁动态塑化挤出机加工ＰＰ／ＣａＣＯ３和ＬＤＰＥ／ＣａＣＯ３时的动态挤出过程,探讨了振动力场对聚合物填充体系挤出过程扣影响规律和作用机理。结果表明,在一定的振动条件下,振动力场的作用使挤出压力减同功率降低,混合分散效果明显提高。     

振动力场作用下聚合物填充体系挤出混合特性

本文利用一种新型毛细管动态流变仪,对碳酸钙填充聚丙烯体系进行了实验性研究。发现质量百分比为８５／１５的ＰＰ／ＣａＣＯ３填充体系,在一较佳振动条件下动态挤出时,振动场的存在对ＣａＣＯ３在ＰＰ熔体中的分散有促进作用,大大改善了混合料的混合程度。     

The effect of a new type of pin mixing section on the performance of a single-screw extruder

The effect of a holed-pin mixing section on the performance of a single screw extruder was investigated and compared with a free flight and a normal pin mixing section, using a practical single-screw extruder. The effect of axial distance between two pins in a holed-pin mixing section on performance was also studied. Mixing ability was quantified using the statistical approach of carbon black concentration distribution in the extruded film mixed with a carbon black masterbatch. The results indicate that a free flight gives the lowest melt temperature rise, pressure drop, and driver power, but the worst mixing; a holed-pin mixing section has better mixing ability, lower melt temperature rise, and lower driver power than a normal pin mixing section does; the value of the pressure drop of the two types of pin mixing sections is approximately identical. A longer axial distance between the two pins in a holed-pin mixing section gives better mixing and lower melt temperature rise than a shorter one; however, when the distance is longer than a critical value, the improvement of mixing is not so outstanding; for different axial distances between two pins, no great change in pressure drop was found and the extrusion throughput has almost no great relation to the axial distance.     

微孔发泡过程中聚合物/超临界CO2均相体系形成的研究

阐述以超临界CO2为发泡剂的微孔发泡中均相体系的形成过程，研究聚合物熔体和气体的混合机理，并分析影响均相体系形成过程的因素。结果表明，聚合物和气体本身的结构和性质、工艺条件、加工设备、外力场等均影响均相体系的形成，振动力场的引入可以提高多相体系的混合程度，在聚合物／气体均相体系的形成过程中引入振动力场是一个全新的研究方向。     

Experimental study on distributive mixing characteristics of a new type of pin mixing section

To eliminate two shortcomings of normal pin mixing sections, namely, the lack of efficient mixing mechanisms and the formation of dead spots, a new type of pin (pins channeled from top-front to bottom-rear) was previously proposed. As an experimental verification of the effectiveness of this type of pin, a dye decoloration experiment with a visual single screw extruder was carried out. The comparative experiments show that a “//” type pin mixing section (the orientation of holes in the pins is parallel) has the best mixing ability; a 45° angle between the projected line of orientation of holes in the pins and the screw axial line provides maximum mixing; however, a 45° angle between the orientation of the pin array and the screw axial direction results in poor mixing. The effect of density of the pins along the screw circumferential and axial direction on distribution mixing was also investigated experimentally.     

Mixing efficiency in a pin mixing section for single‐screw extruders

Non‐Newtonian, non‐isothermal, 3D finite‐element simulation of mixing performance in a pin mixing section with different axial gaps in the pins has been carried out according to their realistic configurations. The quantitative evaluation of mixing ability was based on the theory of kinematics of fluid mixing. To learn and to compare the local mixing performance in a standard screw and a pin mixing section, the local mixing efficiency distribution proposed by Ottino was calculated. Also, the RTDs of these mixers were calculated in an attemt to measure mixing. The integration of the two, namely, the integrating local mixing efficiency along a number of particle pathlines from entrance to exit, together with statistical treatment, which was referred as integral mixing efficiency, then gives a quantitative judgment of the total mixing ability of a continuous mixer. The calculated results showed a nonlinear dependence of the mixing ability of a pin mixing section on the axial gap of the pins. Finally, the calculation results were compared with the experimental ones obtained in our previous study.     

电磁动态塑化挤出机熔体混合性能的研究

在不同振动频率下，利用剖分式料筒电磁动态塑化挤出机，对碳酸钙填充聚乙烯体系进行了螺杆沿程混合性能的研究。通过对不同位置处物料的SEM图的分散相作粒径统计分析。发现振动力场对CaCO3在LDPE熔体中的分散有促进作用。改善了混合物料的混合程度；相同振幅下，振动频率高则分散效果越好。