半硬质聚氯乙烯——超细碳酸钙体系性能的初步研究

本实验应用几种新的填料表面处理剂在PVC 超细CaCO_3体系中。按有关标准进行力学性能测试,考察了填料及处理剂品种、用量对体系性能的影响,同时考察了表面处理剂对体系流变性能的影响;用热分析对体系的“增塑”和稳定效果进行了研究;用扫描电子显微镜观察了超细CaCO_3的形态及其在基体中的分散状态。实验结果表明:所选用的表面处理剂对填充体系的力学性能、流变性能、稳定性、“增塑”效果都有所改善,具有较大的实用价值。同时对这类表面处理剂的作用机理提出了一些新的观点。     

聚丙烯/碳基填料复合材料的流变行为研究

系统研究了炭黑(CB)、石墨(GP)和碳纤维(CF)填充聚丙烯(PP)三种复合材料的稳态、动态流变行为及微观形态;重点讨论了粒子外观形貌、粒径和用量对体系流变行为的影响。研究发现,CB具有强的Payne效应且形成逾渗网络的能力要强于其他两种填料,粒径小的增强效率高、逾渗值低,填料用量增加熔体非牛顿性和弹性增加。使用SEM考察三种填料的微观形态,发现同等含量下,石墨分散性最好,同一填料时,粒径越小分散性越好。     

纳米填料/橡胶体系在贮存中的结构形态变化Ⅱ.结构变化的影响因素及其对性能的影响

综述了纳米填料／橡胶复合体系在熔融态或高弹态贮存停放过程中,影响其结构形态变化的因素,以及贮存停放对复合体系流变性能、物理机械性能和导电性能的影响,并评述了相关的理论模型。纳米填料／橡胶复合体系在熔融贮存过程中的结构变化主要受橡胶的黏度、填料特性及其用量、填料与橡胶之间的相互作用以及加工性能的影响。填料网络结构的絮凝程度强化使复合体系流变性能、动态力学性能降低,但导电性能提高。相关的填料聚集动力学和填料絮凝模型大部分是唯象模型。     

振动共混转矩流变仪及其应用

介绍了振动共混转矩流变仪.该仪器既可以进行稳态共混研究,也可以进行振动共混对聚合物流变性能或者物理过程(如相态和结晶及熔融)影响的研究.所建立的流变模型可以分析聚合物共混物熔体粘度相对高低;应用Lee等分析稳态共混过程共混物相形态演变的方法基本适应振动共混过程,但必须注意振动流场的特点;振动共混过程可以影响制备10/90 UHMWPE/PP结晶的晶体类型和熔融行为.     

流动分散剂RL22和WB222在NBR中的应用研究

对比研究了流动分散剂RL22、WB222与邻苯二甲酸二辛酯(DOP)对丁腈橡胶(NBR)的流变性能、门尼松弛、门尼焦烧、硫化特性、物理机械性能以及压缩永久变形的影响。结果表明,均为饱和脂肪酸酯的RL22、WB222对NBR胶料具有优良的润滑和填料分散效果,胶料的加工性能优于DOP;两者对胶料的硫化性能、力学性能和老化性能无明显影响。     

软化剂和填充剂对弹性体熔体流变性能和介电响应的影响

正上世纪60年代初开始,在过去的几十年里,对熵在橡胶熔体流变性能中的作用,尤其是流动不稳定性进行了深入研究。尤其研究了橡胶和软化剂间的相互作用,及其对流变数据的影响。另外,还进行了磁流变研究,通过外部磁场影响流变性能。通过流变和介电分析深入研究了高温下橡胶熔体中填料的网状结构。这证实了我们纳米结构填料粒子补强橡胶的基本概念和基础理论。尤其是证明了相邻填料粒子间存在纳米级间隙,间隙由结合聚合物链填充。由于吸附性填料表面的     

动态流变法表征聚丙烯复合材料中粒子的分散效果

通过密炼机熔融共混制备了一种聚丙烯阻燃抗静电复合物,在不同混合时间(10、12和14 min)获得不同粒子分散效果的聚丙烯材料;通过扫描电子显微镜、万能力学测试机、旋转流变仪对其进行表征。电镜显示较长时间密炼的样品中,树脂与阻燃剂界面黏合增强,炭黑团聚减少;对应样品的拉伸断裂伸长率和冲击强度较高。流变测试也说明不同混合时间的粒子填充复合材料的流变性能有差异。通过"两相模型"拟合流变数据定量分析不同分散效果样品中粒子和高分子链的相互作用,粒子对高分子链的应变放大效应、黏弹贡献均随分散效果的变好而增加。     

PP/POE/滑石粉复合材料的制备及其在汽车内饰件中的应用

通过分析聚丙烯(PP)和乙烯-辛烯共聚物(POE)的流变特性,选用熔体黏度相近的材料作为基体,以滑石粉为填料,制备了PP/POE/滑石粉复合材料.研究了螺杆组合、助剂种类对复合材料性能的影响,并利用扫描电子显微镜观察了POE和滑石粉在复合材料中的分散情况,考察了该复合材料在改善汽车内饰件外观中的应用状况.结果表明,合适...     

一种新的填料分散技术(一)

增强聚合物的性能不仅依赖于填料特性,还和填料的分散以及在聚合物-填料界面产生的相互作用有关。通过使用一种分散助剂和一些偶联剂,可以优化复合材料的最终性能。今天,硅烷被广泛用作偶联剂和增粘剂,而且还作为填料分散助剂用于聚合物基体中。道康宁(Dow Corning)公司的Valerie Smits、Pierre Chevalier、Damien Deheunynck和Scott Miller概述了硅烷处理对复合材料性能的影响,并介绍了分散助剂的新产品系列。     

碳酸钙分散状态对硅橡胶流变性能的影响

使用3种纳米活性碳酸钙为填料制备室温硫化硅橡胶材料,通过透射电子显微镜观察碳酸钙在硅橡胶中的分散状态,分析碳酸钙分散状态对其流变性能的影响。结果表明,碳酸钙在硅橡胶中的分散状态与其二次团聚程度有关,填料的团聚与网络结构化均会使硅橡胶的储能模量产生显著变化,温度扫描也能反映碳酸钙在硅橡胶中的分散状态。     

大分子键合处理CaCO3的表面性质及其与PVC的界面特性

研究了以大分子键合方式包覆处理CaCO3粉末的表面性质及其填充PVC的界面性质和力学性能,结果表明:①与未处理的CaCO3相比,所有改性CaCO3的表面张力均明显下降,其中表面张力的极性分量大幅度下降,但色散分量略有提高,与PVC的界面张力及其极性分量和色散分量均下降;②用大分子弹性体键合方式处理的CaCO3对PVC填充材料具有明显的增韧效果,其效果优于铝酸酯偶联剂,显示出良好的应用前景。     

Polyethylene toughened by CaCO3 particle: Brittle-ductile transition of CaCO3-toughened HDPE

The dependencies of the notched Izod impact toughness of HDPE / CaCO₃ blends on CaCO₃ particle concentration and particle size are analyzed. It was found that the notched Izod impact strength (S) of HDPE / CaCO₃ blends depends discontinuously on CaCO₃ particle concentration. A brittle-ductile transition occurs when the CaCO₃ volume fraction (V_f) increases to a critical value (Vη_f). Furthermore, a brittle-ductile transition master curve can be constructed by taking the matrix ligament thickness (L) into account as a parameter instead of V_f. The results show that the critical matrix ligament thickness (L_c) is a single parameter for the transition and L_c = 5.2μm for HDPE / CaCO₃ blends. The impact strength, however, varies considerably with CaCO₃ particle size, which shows that CaCO₃ particle size is another dominating parametor for the toughness of HDPE / CaCO₃ blends. © 1993 John Wiley & Sons, Inc.     

Polystyrene/CaCO3 composites with different CaCO3 radius and different nano‐CaCO3 content—structure and properties

The Archimedes' principle and physical theory are attempted to analysis the densification and structure of the polystyrene (PS) composites by melt compounding with CaCO₃ having different particle size. The difference between the measured specific volume (ν) andthe theoretically calculated specific volume (ν_mix), Δν = ν−ν_mix, can reflect the densification of the composites. It is clearly demonstrated that the PS composites become more condensed with the reduction of the CaCO₃ particle size. Especially, when the content for nano‐CaCO₃ achieves 2 wt%, the Δν value of the composites reaches the least, which shows the best densification. Meanwhile, the glass transition temperature (T_g) reaches the maximum value of about 100°C by differential scanning calorimetry (DSC) and thermal mechanical analysis (TMA), which indirectly reveals the composites microstructure more condensed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that 2 wt% nano‐CaCO₃ uniformly disperses in PS composites. The CaCO₃ selected in this experiment has certain toughening effect on PS. The impact and tensile strength increase with addition of nano‐CaCO₃, but the elongation at break decreases. When nano‐CaCO₃ content achieved 2 wt%, the impact and tensile strength present the maximum value of 1.63 KJ/m² and 44.5 MPa, which is higher than the pure PS and the composites filled with the same content of micro‐CaCO₃. POLYM. COMPOS., 31:1258–1264, 2010. © 2009 Society of Plastics Engineers     

聚合物包覆对纳米CaCO3在PVC中分散的影响

以偶联改性纳米CaCO3和甲基丙烯酸甲酯（MMA）为原料,原位乳液聚合制得PMMA接枝包覆纳米CaCO3,以其与PVC熔融共混制备复合材料,研究了纳米CaCO3在共混体中的分散和与PVC界面的结合.与未改性纳米CaCO3相比,纳米CaCO3接枝包覆PMMA后,在PVC中的分散性能得到明显改善,粒子被分散得更加细小、均匀.PMMA接枝包覆纳米CaCO3与PVC界面间相容性能最好,比小分子改性CaCO3与PVC间的黏结作用更强.采用PMMA包覆纳米CaCO3粒子改性PVC,比未改性纳米CaCO3改性PVC有更好的冲击性能及拉伸性能.     

超细碳酸钙的制备

综述了超细碳酸钙的生产方法,重点介绍了粒径小于０．１μｍ的方立形和链锁形碳酸钙的制备方法。     

纳米CaCO3的表面改性研究

本文研究了纳米CaCO3表面改性的影响因素，确定了最优改性剂和改性条件，并运用沉降实验、透射电镜（TEM）等表征手段对粉体的改性效果进行了分析。结果表明：以月桂酸钠为改性剂，用量为10％，pH值为7，改性时间为1h时，改性后的纳米CaCO3的亲油化度达到85．1％，能较好地分散于环己烷和二甲苯中。     

Plasticization of nano‐CaCO3 in polystyrene/nano‐CaCO3 composites

The shear rheological properties of polystyrene (PS)/nano‐CaCO₃ composites were studied to determine the plasticization of nano‐CaCO₃ to PS. The composites were prepared by melt extrusion. A poly(styrene–butadiene–styrene) triblock copolymer (SBS), a poly(styrene–isoprene–styrene) triblock copolymer (SIS), SBS‐grafted maleic anhydride (SBS–MAH), and SIS‐grafted maleic anhydride were used as modifiers or compatibilizers. Because of the weak interaction between CaCO₃ and the PS matrix, the composites with 1 and 3 phr CaCO₃ loadings exhibited apparently higher melt shear rates under the same shear stress with respect to the matrix polymer. The storage moduli for the composites increased with low CaCO₃ concentrations. The results showed that CaCO₃ had some effects on the compatibility of PS/SBS (or SBS–MAH)/CaCO₃ composites, in which SBS could effectively retard the movement of PS chain segments. The improvement of compatibility, due to the chemical interaction between CaCO₃ and the grafted maleic anhydride, had obvious effects on the rheological behavior of the composites, the melt shear rate of the composites decreased greatly, and the results showed that nano‐CaCO₃ could plasticize the PS matrix to some extent. Rheological methods provided an indirect but useful characterization of the composite structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Influence of strain rate on the toughening effect of CaCO3 in polypropylene/CaCO3 composites

The effects of 40 and 50 wt% of calcium carbonate on the mechanical properties of polypropylene were investigated by uniaxial tensile deformation at room temperature and at loading rates of 5, 50, and 125 mm/min. The results showed that the addition of calcium carbonate to polypropylene decreased yield strength while increasing modulus. The decreases yield strength was attributed to the poor adhesion between filler and matrix. The tensile toughness of polypropylene was improved by the addition of calcium carbonate particles at constant strain rate because of the plastic deformation of interparticle ligaments following particle‐matrix debonding. The (strain rate) sensitive behavior of the composites (at constant calcium carbonate content) was observed. J. VINYL ADDIT. TECHNOL., 19:271–275, 2013. © 2013 Society of Plastics Engineers     

纳米级CaCO3填充HDPE复合材料的研制

研究了纳米级ＣａＣＯ３填充ＨＤＰＥ体系的力学性能和流变性能,发现这种填充体系的脆韧变消失,且具有良好的加工性能和优良和综合性能。     

稀土钛偶联剂对CaC03改性及其在PE-LLD中的应用研究

采用万能试验机、转矩流变仪和旋转黏度计等研究了新型稀土钛偶联剂对不同粒径重质碳酸钙（CaCO3）的偶联处理及其对PE—LLD／CaCO3复合体系的力学性能和流变性能的影响。结果表明，稀土钛偶联剂改性的不同粒径CaCO3填充的复合体系的力学性能和流变性能得到很大改善；其中，稀土钛偶联剂处理粒径18μm重质CaCO3效果最好，当偶联剂含量为1．2％（质量分数，下同）时，复合体系的断裂伸长率、拉伸强度和拉伸弹性模量分别比未改性的提高了14．7％、12．5％和10．3％，而最大扭矩和平衡扭矩比未改性的分别降低了11．4％和9．6％；其改性效果均优于钛酸酯和铝酸酯偶联剂。实验表明稀土钛偶联剂处理的CaCO3在非极性液体石蜡中有较好的分散性和相容性。