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.     

CPE包覆纳米CaCO3对PVC／纳米CaCO3复合材料结构与性能的影响

研究了基体韧性、纳米CaCO3直接填充与用CPE包覆后填充PVC对复合材料力学性能的影响，并对其微观结构进行了探讨。结果表明，适当的基体韧性有助于获得较高的冲击强度；两种填充方法下，PVC复合材料的冲击强度和拉伸强度呈现出不同的变化趋势。包覆处理填充体系的冲击强度均要比未包覆处理填充体系的略低，而拉伸强度则相反，特别是在包覆小份量CaCO3(2份)时，所得复合材料的冲击强度甚至比PVC／CPE(8份)基体的低12％，而拉伸强度则出现最大值，比基体的高8．9％左右。     

PVC与纳米碳酸钙复合材料的结构与性能研究

采用拉伸强度、断裂伸长率、冲击强度等力学参数对聚氯乙烯(PVC)/纳米CaCO3复合材料进行评价,并结合热重差示扫描量热仪、扫描电镜对复合材料的热稳定性和断面结构进行表征.结果表明:采用超声分散方法,选用NDZ-311/SG-Al 821复合改性剂改性的纳米CaCO3明显提高了PVC基复合材料的缺口冲击强度、断裂伸长率和热稳定性;当纳米CaCO3填充质量分数达15%时,PVC/纳米CaCO3复合材料的缺口冲击强度达22.34 kJ/m2,比未填充纳米CaCO3的提高了60.5%;当纳米CaCO3填充质量分数不高于20%时,用超声技术改性纳米CaCO3能很好地分散在PVC基体中.     

PVC/CaCO3纳米复合材料结构与性能的研究

研究了PVC／CaCO3纳米复合材料的力学性能和热性能,观察了复合材料冲击缺口的断面微观形态和纳米CaCO3粒子在PVC中的分散情况。结果表明：当纳米CaCO3粒子的质量分数为10％时,PVC／CaCO3纳米复合材料的冲击强度提高了约365％,拉伸强度略有提高;当纳米CaCO3质量分数超过10％以后,纳米粒子在基体中的分散情况变差;随着纳米CaO3用量的增加,PVC／CaCO3纳米复合材料的玻璃化转变温度先降后升。     

纳米CaCO_3的接枝改性及其填充PVC复合材料的性能

采用表面原位接枝聚合在纳米CaCO3颗粒表面引入聚甲基丙烯酸甲酯(PMMA)或聚丙烯酸丁酯(PBA),用共混法制备了纳米CaC03/PVC复合材料,研究了不同界面特性时纳米CaCO,/PVC复合材料的力学性能.研究结果表明:通过表面原位接枝聚合反应可以在纳米CaCO3颗粒表面接枝PMMA和PBA;表面接枝聚合改性大大促进了纳米CaCO3粒子在PVC基体中的分散行为,增加了复合材料的拉伸强度以及与聚合物的界面粘接强度,但复合材料的冲击强度有所下降.     

弱界面无机刚性粒子改性UPVC力学性能的研究

考察了硬脂酸包覆沉淀CaCO3的粒径、用量及塑炼温度对UPVC力学性能的影响。研究结果表明:减少CaCO3用量或CaCO3的粒径均有利于获得较高的屈服强度;增加CaCO3的用量或减少所用CaCO3的粒径均有利于UPVC弹性模量提高;适当增加亚微米或纳米CaCO3的用量可提高PVC的缺口冲击强度,亚微米CaCO3的最佳用量为15份,纳米CaCO3的最佳用量为40份。为了获得力学性能优化的UPVC,填充亚微米CaCO3的UPVC宜于较高温度加工,填充纳米CaCO3的UPVC宜于较低温度加工。在纳米CaCO3填充的UPVC中,仅用少量CPE即可得到超韧的UPVC材料。     

高分子包覆纳米CaCO3的制备及其在PS中的应用

用丙烯酸（AA）与苯乙烯（St）及丙烯酸甲酯（MA）与苯乙烯（St）共聚包覆改性纳米CaCO3，通过红外光谱及透射电镜对改性前后纳米CaCO3的结构和微观形貌进行了表征，利用改性后的纳米CaCO3填充聚苯乙烯（PS），测试了PS／纳米CaCO3复合材料的力学性能。结果表明包覆改性后的纳米CaCO3对，PS有增强增韧作用。经MA与St共聚包覆改性的纳米CaCO3比用AA与St共聚改性的纳米粒子更能提高PS／纳米CaCO3复合材料的力学性能，其拉伸强度及无缺口冲击强度分别比纯PS提高14％和21％。     

纳米CaCO3原位聚合PVC树脂的生产及加工应用

研究了纳米CaCO3的加入对氯乙烯原位悬浮聚合体系温度、压力及树脂性能的影响。结果显示：纳米CaCO3的加入，加剧了体系的聚合反应，压降提前出现；随着纳米CaCO3加入量的增大，树脂白度(按GB/T15595测定)由83％增加到86％，其它指标变化不大。将所得树脂用于PVC制品的加工应用，考察了其物理性能，结果显示：与同型号未改性PVC树脂相比，该树脂扭矩、物料熔融温度、产率、动态热稳定性等指标均有提高；随着纳米CaCO3加入量的增加，测试样冲击强度由3．68kJ／m^2增加到7．09kJ／m^2，拉伸强度由40．4MVa降低到37．2MVa，其它指标变化不大。     

CaCO3／PVC纳米复合材料的研究

研究了经过表面改性的纳米CaCO3添加量对PVC／米CaCO3复合材料聚合工艺和力学性能的影响。结果表明,纳米CaCO3经过处理后,表面包覆了一薄层的有机物。纳米CaCO3在3％-7％的添加范围内,可以缩短聚合反应时间。纳米PVC与普通PVC比较,冲击强度可提高到9．38kJ／m^2,断裂伸长率在拉伸强度略有降低的前提下增大到60．2％。纳米CaCO3的添加量为7％时,可以得到综合性能较好的纳米CaCO3／PVC复合树脂。     

PVC/CaCO3复合材料的结构与性能研究

研究了表面改性微米重质CaCO3填充的聚氯乙烯（PVC）树脂所得PVC／CaCO3复合材料的结构和热力学与机械性能。结果表明，改性微米重质CaCO3的填充能明显提高PVC基复合材料的缺口冲击强度和维卡软化温度。当填充质量分数20％的改性微米重质CaCO3后，PVC／CaCO3复合材料的冲击强度为20．92kJ／m^2，比未加微米重质CaCO3的提高了49．9％。扫描电镜（SEM）观察复合材料的表面形态，发现拉伸断面有拉丝现象。热失重-差示扫描量热分析发现，微米重质CaCO3对PVC基复合材料分解有一定的抑制作用。     

Physical Properties of Plasticized Poly(vinyl chloride) Blended with Poly(methyl methacrylate) Nanoparticles Synthesized by Differential Microemulsion Polymerization

In this work, poly(methyl methacrylate) (PMMA) nanoparticles synthesized by differential micro emulsion polymerization were used to improve the physical properties of plasticized poly(vinyl chloride) (PVC). PVC, plasticizer (40 phr), heat stabilizer (2 phr), and lubricant (0.2 phr) were melt-mixed with varied amount of the PMMA nanoparticles (3, 5, 7, and 9 phr) on a two-roll mill, followed by compression molding. The results showed that the tensile strength, Young's modulus, tear strength, and thermal stability were improved, but the elongation at break deteriorated with increased PMMA content. Moreover, the flammability of the plasticized PVC was not improved by the PMMA nanoparticles.     

弱界面无机粒子填充PVC-U形变与韧化的微观机理

观测了硬脂酸包覆CaCO3 粒子填充PVC U受力形变过程的相结构演变。至屈服点 ,刚性粒子两极与基体脱开形成孔穴 ;进而通过分子链段的运动 ,基体与孔穴沿外力取向 ;最终因分子链断裂或滑脱 ,孔穴合并迅速扩大 ,并使基材破裂。缺口冲击断裂的机制与拉伸断裂相似 ,大量基体分子沿外力的取向与滑移使材料韧化。弱界面无机粒子的作用在于造成适当尺寸与间距的微孔穴 ,大量基体分子的取向在微穴的诱导下进行 ,由此而使基材韧化。     

改性凹凸棒土填充硬质PVC的制备与性能研究

用硅烷偶联剂甲基丙烯酰氧丙基三甲氧基硅烷（MPTMS）和甲基丙烯酸甲酯（MMA）和凹凸棒土（AT）进行表面接枝改性，用傅立叶红外光谱分析了改性凹凸棒土的表面化学结构。以改性的凹凸棒土填充硬质聚氯乙烯（PVC），测试了材料的力学性能和热性能，结果表明，改性凹凸棒的填充可使PVC复合材料的拉伸强度，缺口冲击强度，弯曲强度，弯曲模量和热稳定性等均有所提高，用透射电镜观察了凹凸棒土及其在PVC基体中的微观分散状况，凹凸棒上具有纳米尺寸的针状结构，在PVC基体中以直径20nm-60nm,长度100nm-500nm的短纤维状分散在其中。     

Study of the solvent effect on miscibility between poly(vinyl chloride) and poly(methyl methacrylate) in the solution state – viscometric measurements

In this work, the solvent effect on the miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in ternary polymer solutions was examined by the viscometric method. In these systems, we could understand that the used solvents, tetrahydrofuran (THF) or N,N‐dimethylformamide (DMF), mainly affect the interaction between PVC and PMMA, while prompting various miscible properties. In PVC/PMMA/THF solution, THF is a near θ‐solvent and a poor solvent for PVC and PMMA, respectively. The mixing of the tighter PMMA coils and more extended PVC coils in THF may cause the sea–island heterogeneous structure below the weight fraction of PMMA in the polymer mixture w_PMMA = 0.7, resulting in immiscible PVC/PMMA mixtures. At w_PMMA ≥ 0.7, the PVC/PMMA mixtures are relatively miscible, giving homogeneous polymer solutions. It means that the miscibility between PVC and PMMA depends on the composition of polymer mixture. However, due to the similar affinity of DMF to PVC and PMMA, PVC/PMMA/DMF solutions exhibit high miscibility between PVC and PMMA at about w_PMMA = 0.5. © 2000 Society of Chemical Industry     

CPE对纳米CaCO3增韧PVC复合材料界面和性能的影响

研究了CaCO3/CPE(氯化聚乙烯)/PVC(聚氯乙烯)纳米复合材料的结构和性能,探讨了CPE对纳米CaCO3/PVC复合材料界面作用和力学性能的影响. SEM结果显示,引入CPE可明显改善纳米CaCO3颗粒在PVC基体中的分散性和相容性,提高其界面作用. 引入界面作用参数定量表征纳米CaCO3颗粒与基体之间的界面结合作用,证实随着CPE加入量的增大,基体和颗粒之间的界面作用逐渐增大. 力学性能研究表明,相对于仅用纳米CaCO3增韧PVC,在CPE加入量为PVC的0~8%(w)范围内,用CPE和纳米CaCO3协同增韧可以更好地提高复合材料的冲击强度. 复合材料的冲击强度在CaCO3/CPE/PVC质量比为25/8/100时达到纯PVC的5.6倍,是纳米CaCO3/PVC(25/100)体系的2倍.     

改性碳酸钙用于聚氯乙烯的研究

研究了一种改性碳酸钙的性质及其在聚氯乙烯中的应用情况。研究结果表明，这种改性碳酸钙与普通碳酸钙相比，具有吸油值低、堆积密度大、分散性好、热稳定性高等特点。填充于聚氯乙烯中，不仅能改善物料的加工性能及制品的物理力学性能，而且还具有较高的热稳定性能。     

Influence of the tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl chloride)

It can be concluded from the work of Schurer et al.¹⁰ that poly(vinyl chloride) (PVC) is more miscible with syndiotactic than with isotactic poly(methyl methacrylate) (PMMA). By choosing different molar masses for the various tactic forms of PMMA it is possible to obtain blends with PVC with similar phase behaviour, i.e. in all cases a cloud-point curve with a minimum in the vicinity of 190°C. In this way a more quantitative statement about the influence of the tacticity of PMMA on its miscibility with PVC can be made. One of the principal differences between syndiotactic or atactic PMMA and isotactic PMMA is the higher flexibility of the latter. Using Flory's equation of state theory it will be shown that the effect of this difference is large enough to explain the difference in phase behaviour observed. Heats of mixing of low molar mass analogues were also measured and found to be negative.     

Tensile properties of a poly(vinyl chloride) composite filled with poly(methyl methacrylate) grafted to oil palm empty fruit bunches

The influence of oil palm empty fruit bunch (OPEFB) fiber and oil palm empty fruit bunches grafted with poly(methyl methacrylate) (OPEFB‐g‐PMMA) on the tensile properties of poly(vinyl chloride) (PVC) was investigated. The OPEFB‐g‐PMMA fiber was first prepared with the optimum conditions for the grafting reaction, which were determined in our previous study. To produce composites, the PVC resin, OPEFB‐g‐PMMA fiber or ungrafted OPEFB fiber, and other additives were first dry‐blended with a laboratory blender before being milled into sheets on a two‐roll mill. Test specimens were then hot‐pressed, and then the tensile properties were determined. A comparison with the composite filled with the ungrafted OPEFB fiber showed that the tensile strength and elongation at break increased, whereas Young's modulus decreased, with the incorporation of 20 phr OPEFB‐g‐PMMA fiber into the PVC matrix. The trend of the tensile properties obtained in this study was supported by functional group analysis, glass‐transition temperature measurements, and surface morphological analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

硅灰石填充改性硬质聚氯乙烯的研究

考察了两种硅灰石刚性粒子填充硬聚氯乙烯的力学性能。结果表明，在一定的填充量范围内，两种硅灰石都能提高PVC的冲击强度，硅灰石粒子表面包覆了聚甲基丙烯酸甲酯改性处理后，对基体树脂的力学性能改善明显，尤其是小粒径的改性硅灰石刚性粒子改进更大。另外，还结合电子显微镜观察对共混体系的增韧机理进行了讨论。