聚甲醛在新型陶瓷注射成型催化脱脂工艺中的应用

利用聚甲醛对酸性气氛敏感易分解的特性，将其作为主要粘结剂应用于陶瓷注射成型技术中，并采用了新型的催化脱脂技术，使得脱脂速度有了很大提高，实验样品主要粘结剂的脱除量在10h内即达到90％以上，记录了该过程中样品失重的情况，分析了脱脂阶段不同特征及其原因，指出催化脱脂过程速度的控制因素是气态催化剂和气体产物扩散过程，实验观察了脱脂过程不同时刻样品外围与中心区域的微观形貌，证明了脱脂过程由外围逐渐向内部扩散，对物料流变性能的考察表明物料为假塑性，有良好的流动充模性。     

Fast online acquisition and analysis for parison swell and sag in blow molding

It is critical to quantitatively and reliably characterize the effects of swell and sag phenomena on the final parison dimensions in extrusion blow molding. To achieve this goal, an online image acquisition and analysis technique was developed. The successive images of parison were automatically taken using the online acquisition apparatus. These images were then analyzed by the combined use of the conventional digital image processing method and the new one developed by the authors. So the development of parison diameter and thickness swells with the extrusion time could be determined online. On the basis of the online obtained actual swell values, the pure swell and sag components were quantitatively determined. The developed technique was tested through a series of experiments using several resins under different processing parameters and die types. Shown in the present article were the results for a converging die under three different die gaps and a high‐density polyethylene. Some new phenomena were observed using the proposed technique. The results showed that the technique yields fast and accurate determination of the evolution of diameter, thickness, and length of parison during its extrusion. The technique can be employed as a part of the closed loop control for blow molded part thickness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2399–2406, 2006     

振动力场对聚丙烯/纳米碳酸钙复合材料性能的影响

采用自行研制的振动注射装置在注射保压过程中对聚合物熔体施加低频振动,成型了聚丙烯/纳米碳酸钙复合材料。对样品进行了力学性能测试并采用SEM对它的冲击断面进行研究。结果表明,采用振动注射成型装置可以使碳酸钙粒子在基体中的分散性得到改善。与常规注射相比,经振动注射后,复合材料的拉伸强度提高了17.6%,冲击强度提高了179.6%。     

旋转注射式反应注射成型技术混合方式剖析

为了克服反应注射成型技术混合方式存在的缺点，新近出现了一种旋转注射式－ＲＩＭ技术。该技术采用低速旋转注射剪切层流混合方式，具有能耗低，混合效果好，应用广泛等特点，是一种很有应用潜力的新技术，文内对该技术的混合方式进行了简要剖析。     

陶瓷注射成形技术进展

陶瓷粉末注射成形是从现代粉末注射成形技术中发展起来的一项新型成形技术。本文着重论述了陶瓷注射成形发展的历史、技术特点、工艺及进展情况，并介绍了CIM的典型产品和应用领域。     

聚合物流变性能对共注射成型的影响

在共注射成型多相分层流动充模成型机理的基础上，揭示了芯壳层熔体对共注射成型的分层界面形貌和芯层熔体前沿突破的影响，并模拟了芯壳层熔体粘度比对共注射成型的影响，建立了芯壳层熔体粘度与分层界面和前沿移动界面菜貌的关系。本文的模拟研究结果与一些文献的实验结果相吻合。     

Amplification effect of platelet type nanoparticles on the orientation behavior of injection molded nylon 6 composites

The effect of platelet type nanoparticles and processing conditions; mold temperature and injection speed, on the development of local microstructure in injection molded nylon 6 parts was investigated. The molded parts exhibit two crystal forms (α and γ) of nylon 6 in varying proportions from skin to core. The γ crystals preferentially grow near the surface regions and α crystal fraction increases with distance from the surface in all molded parts. However, the spatial variation of crystal phases across the thickness in nanocomposites differs from that of unfilled nylon 6. Nanoplatelets induce high levels of orientation of the polymer matrix throughout the thickness of the molded part even at high mold temperatures where nonisothermal effects are highly suppressed and confined to very close proximity of surfaces. These high chain orientation levels observed in nanoparticle filled systems is a result of the shear amplification effect that occurs in small spaces between adjacent nanoparticles of differing velocity. The local preferential crystalline orientation of nylon 6 resin and nanoparticles across the thickness of the molded parts are investigated using a series of structure characterization techniques including microbeam wide angle X-ray, SAXS and TEM.     

扫描仪面框注塑件翘曲变形的模拟分析

以扫描仪面框薄壁件注塑成型为例，应用Moldflow软件分析了模具温度、熔体温度、浇口位置和保压参数对翘曲变形的影响规律，提出了减小翘曲变形的工艺措施，分析结果与生产实际吻合。     

Numerical analysis on reaction injection molding of polyurethane foam by using a finite volume method

Foam reaction injection molding (FRIM) is one of the most popular and useful processes for producing polyurethane foam with a complex geometry. A theoretical model which includes chemical reactions, foaming, and mold filling was developed to analyze FRIM. Energy balance equation was derived by considering polyurethane reaction, water-isocyanate reaction, and evaporation of physical blowing agents. Density and viscosity model was proposed for the bubble suspension, which was assumed to be a homogeneous phase. Based on the theoretical model, three-dimensional numerical simulation for mold filling of the polyurethane foam was carried out to predict flow field, flow front advancement, and density distribution during mold filling. Mold filling of a refrigerator cavity was investigated numerically. The density and thermal conductivity of the foam in the flow front was higher than those in the initially filled region.     

蓄能器在全液压注塑机的应用以及节能效果研究

为了节约传统液压注塑机液压阀溢流损耗能量,对传统的全液压注塑机的油路进行改造,加入自行研制的蓄能器节能模块;对改造完成的节能注塑机进行能耗测试并与未改造的传统注塑机进行能耗比较,发现蓄能器模块加入液压注塑机后的整机能耗有明显降低,能实现预期的节能降耗目的;在不同的塑化注射压力下、不同的塑化背压下、不同保压时间下,对节约能耗数据进行测量分析,并从机理上分析能耗数据的差异,研究蓄能器模块使液压注塑机能耗降低的原因.