聚氯乙烯干混料塑化行为的研究

本文采用XSS—300转矩流交仪,在一定转数和温度条件下测定了我院研制的聚氯乙烯搪塑用干混料和西德样品的扭矩随时间变化关系,并绘制出了扭矩与时间关系曲线即塑化曲线,对所得的塑化曲线进行分析,指出曲线中各个特征值的物理意义及实用价值,同时对不同样品的特征值加以对比,评价其塑化性能,并对其塑化行为进行了研究。     

PVC干混料的塑化特征及新型加工助剂JZ-W的作用

系统研究了聚氯乙烯(PVC)干混料在HAKEE转矩流变仪中的塑化过程,并从能量损耗的角度探讨了不同投料量、转速以及温度对PVC干混料的塑化特征的影响。结果表明,不同投料量、转速、温度下,PVC干混料的扭矩-时间曲线形态基本一致;但随投料量和转速增加,塑化时间缩短,能耗增加;外加温度的增加可使塑化时间和机械能耗同时减小。2 phr新型加工助剂JZ-W的引入,使干混料的塑化时间缩短约20%,而能耗仅增加6%。     

注塑机塑化工艺参数对塑化能耗的影响

通过对塑化理论与能量热平衡的分析,提出了塑化过程单产能耗计算公式,以全液压注塑机为研究对象,并借助Origin数据分析软件,讨论了螺杆转速、塑化背压以及机筒平均温度3个工艺参数对塑化能耗的影响。结果表明:塑化能耗随着螺杆转速、机筒平均温度的升高而降低,随着塑化背压的升高而升高。     

注塑机塑化参数对能耗的影响研究

通过对料筒平均温度、背压、转速建立正交试验表,模拟计算这些因素对能耗的影响程度,得到注塑一个产品在不同参数下需要消耗的功率和各参数对能耗的影响程度,然后通过实验验证模拟结果,证实了该研究方法的正确性及可靠性,该方法为注塑节能和塑化参数方案的确定提供一定依据.     

用高速混合机制备硬质PVC干混料生产过程研究

以生产用高速混合机为主,并结合转矩流交仪和差动热分析仪,在硬质PVC制品(如硬板、透明板、发泡板、异型材、硬管和管件等)的加工过程中,对高速混料过程进行了研究。研究表明,混料过程不是简单的机械混合,而是一个复杂的高分子物理过程,有液态组分向PVC树脂颗粒的渗透和扩散,有高聚物的三态(玻璃态、高弹态和粘流态)的转变,有PVC树脂颗粒的变形、破裂和合并。因而高速混合工艺过程是PVC加工过程中重要一环,必须重视。研究中还发现,转矩流变数据和差动热分析数据对高速混合过程有指导作用。     

PVC干混料粉体流动性的影响因素

介绍了与粉体流动性有关的理论,分析了PVC树脂、CPE、碳酸钙和冷混工艺对PVC干混料粉体流动性的影响,结果表明:①乙烯法PVC树脂的粉体流动性一般优于电石法PVC树脂,且波动较小;②某些厂家的冲击改性剂CPE可改善PVC干混料的粉体流动性,并且随着CPE用量的增加,PVC干混料的粉体流动性增加;③不同生产厂家的PVC/CPE体系对PVC干混料粉体流动性的影响规律不同,应不断摸索,找出最佳组合;④随着碳酸钙用量的增加,PVC干混料的粉体流动性降低,特别是在料斗上的表现更为突出;⑤充分冷却后的PVC干混料粉体流动性较好。     

螺杆参数对注射机塑化单产能耗影响的实验研究

对注塑螺杆计量段槽深h3、长度L3、螺距S和螺杆与机筒内壁间隙δ四个因素建立正交试验,设计并加工实验所用的9根螺杆,通过转矩传感器测得螺杆塑化时的转矩和功率,计算出螺杆塑化时消耗的单产能耗,通过正交实验级差分析,给出了不同螺杆参数对塑化单产能耗影响因素的大小顺序.最后结合螺杆混合效果给出实验中混合最优能耗最低的螺杆参数,为实际生产中设计节能型螺杆提供了依据.     

流变仪对PVC干混料流变性能的评价

介绍了流变仪对PVC干混料流变性能的评价以及其影响因素,认为通过流变曲线可评价PVC干混料的加工性能,以指导生产。     

发泡注塑过程中注射及塑化能耗分析

通过正交试验采集发泡注塑实验过程的工艺参数、功率等数据,以螺杆位移曲线的变化为参考确定注塑周期各阶段上的能耗分布。对其中的注射和塑化能耗及影响因素进行了方差分析,分析结果表明:工艺参数的变化对注射能耗影响更大,在较高的螺杆转速和注射速度下能耗较低。     

Correlations between extrusion and injection molding process variables for PVC dry blends

Although thermoplastic extrusion and injection molding have been extensively studied by a large number of authors, very little is known about the correlations between the extrusion and injection molding process variables. This paper describes the various comparable process variables between extrusion and injection molding of PVC dry blends. The Brabender extruder of 19 mm diameter and 25:1 length to diameter ratio and the Szekeley reciprocating single screw injection molding machine were used. PVC dry blends of industrial importance were prepared using a high speed mixer. The four mix formulations based on a commercial grade of PVC were used. Process variables studied during the injection molding were the melt temperature near the nozzle, injection pressure, injection speed, and energy consumption. Process variables studied during extrusion were the melt pressure at the die, power consumption, and the melt temperature at the die orifice. The correlations between the extrusion and injection molding process variables for PVC dry blends have been established.     

关于PVC生产工艺节能降耗的几点设想

就PVC生产工艺过程中的热量回收以及低沸塔顶部所排尾气的回收问题，结合国内几家PVC生产厂家的生产工艺，经总结和分析，提出了几点设想，同时也探讨了PVC生产过程中尾气所含乙炔的回收问题。     

Factors affecting the abrasiveness of filled rigid PVC dry blends

Abrasion due to the high speed mixing of rigid PVC dry blends filled with CaCO₃ was found to be a function of both the mixing conditions and type and level of CaCO₃ used. Laboratory scale tests showed that abrasion is a function of mix time, mix speed, and mixer blade geometry. These variables were standardized to develop a laboratory abrasion test using a Hockmeyer mixer equipped with a soft 3-in diameter aluminum mixing blade. This procedure was used to investigate the effect of CaCO₃ property variables on abrasion during rigid PVC dry blending. Multiple linear regression analysis at 30 phr CaCO₃ showed that abrasion increased with filler top cut, mean, acid insolubles, and MgCO₃ content, but diminished with an increase in percent less than 1 micron fraction. A more generalized abrasion predictor model was developed by considering surface area to be a linear function of top cut, mean, and percent less than 1 micron properties. Abrasion was greatly minimized by using finer particle size, higher surface area CaCO₃ with low acid insoluble and magnesium carbonate levels. These criteria also aid in reducing the abrasive effects of TiO₂ during dry blending through a CaCO₃/TiO₂ interaction.     

环氧低热油的制备及其增塑性能

选用常用来合成环氧大豆油和环氧脂肪酸甲酯的大豆油为原料,运用GC-MS联用仪测定了其组成及含量,并通过酯交换、环氧化等工艺合成了具有环氧结构的环氧长短链酰基甘油酯（环氧低热油）;并对其作为聚氯乙烯增塑剂的各项性能进行了研究。结果表明,大豆油不饱和脂肪酸含量达88.5%,当其与三乙酸甘油酯在物质的量之比为1∶1的情况下可得到以二脂肪酸单乙酸酯为主要成分的低热油;此外,通过物化性能、动态热机械分析、薄膜拉伸、热重-红外-质谱及热分解动力学等手段分析,结果表明环氧低热油的玻璃化转变温度为–0.77℃,低于环氧大豆油的6.13℃;其断裂伸长率为370.56%,也高于环氧大豆油321.11%;与环氧脂肪酸甲酯相比具有更高的闪点、较少的加热减量和更优良的热稳定性。所以环氧低热油是一种较为优良的增塑剂产品。     

塑化过程振动参数对制品力学性能的影响

采用自制新型液压脉振式注塑机,在塑化过程引入液压脉动,探讨振动参数对制品力学性能的影响。结果表明:施加振动后,低密度聚乙烯、聚丙烯拉伸强度分别提高6.1%,9.8%;密度分别增大0.33%,0.30%;加工能耗分别降低6.8%,6.3%,且呈现一定的变化规律。     

PVC和CPE不同配比对干混料性能的影响

测定了PVC和CPE不同用量配比对制得的干混料性能指标的影响,结果表明:随着CPE用量的增加,干混料的硬度呈现下降的趋势,断裂伸长率急剧上升,拉伸强度急剧下降,塑化性能增加。     

PVC/MBS共混物的断裂研究

采用吴康理论(Vu-Khanh-plot)与扫描电子显微镜照片、冲击强度测试数据相结合,研究聚氯乙烯(PVC)/甲基丙烯酸甲酯-丁二烯-苯乙烯(MBS)三元共聚物的裂纹引发断裂能(Gi)与冲击强度的关系.随着增韧剂MBS含量的增加, PVC/MBS共混物的冲击强度提高, Gi由纯PVC的0.32 kJ/m2增加到4.06 kJ/m2.同时, Gi和冲击强度也随MBS粒径的增大而增大.因此, PVC/MBS共混体系的冲击强度随着Gi的增加而增大.     

PP-g-（DMC-co-St）增容PP／PVC共混体系的研究

利用合成的多单体接枝物[PP-g-（DMC-co-St）]增容PP／PVC共混体系,研究了其用量对共混物力学性能以及流变性能的影响,并通过扫描电镜（SEM）分析了共混物的亚微观相结构。结果表明：①在试验条件下,共混物熔体具有典型的假塑性流体特征,在PP-g-（DMC-co-St）用量为6份时,熔体的表观黏流活化能和非牛顿指数最大;②PP-g-（DMC-co-St）对PP／PVC共混体系有较好的增容效果,增容后在PP-g-（DMC-co-St）用量为6份时,试样的拉伸强度、缺口冲击强度出现最大值,与扫描电镜照片的分析结果一致。     

潜油电泵系统能耗研究

针对潜油电泵的系统能耗问题,结合我国潜油电泵的应用现状,首先对潜油电泵的系统效率进行深入分析,在此基础上,对影响潜油电泵系统能耗的相关因素进行深入研究,分析这些因素出现的原因,并提出降低能耗的相关措施,为推动潜油电泵技术的进一步发展奠定基础。研究表明:参数设计、库存以及结垢等因素都会影响潜油电泵的系统能耗,各因素影响系统能耗的途径各不相同,但是都会给油田单位带来一定的经济损失,因此相关单位必须从这些影响因素出发,采取必要的措施,降低系统能耗。     

Study on compatibilization-crosslinking synergism in PVC/LDPE blends

Influences of nitrile rubber (NBR, acrylonitrile content 33.5 – 36.5 wt.-%) on the structure and mechanical properties of poly(vinyl chloride) (PVC)/low density polyethylene (LDPE) blends and its synergism with crosslinking agent have been studied. The addition of NBR to the blend is accompanied by a decrease in domain size and improvements in mechanical properties of the blend. When dicumyl peroxide (DCP) is added to the blend together with NBR, good synergism is caused and mechanical properties will improve dramatically. It is concluded that NBR can promote the phase dispersion of PVC and LDPE and their interfacial adhesion. Then, the probability of DCP existing at the interface will increase and more co-crosslinked products will form. Therefore, compatibilization and crosslinking are both exerted sufficiently.