纳米CaCO3添加剂对PVC涂层流变性能的影响(英文)

Effect of Nano-CaCO_3 Agents on Rheological Behavior for PVC Coating

制备了一系列经纳米CaCO_3改性的PVC涂层。研究表明,由于氯原子与Zn之间具有较强的络合力,PVC涂层的粘度随着热稳定剂Ba/Zn含量的增加呈线性增加。流变结果发现,当纳米CaCO_3含最≥10%(质量分数)时,其储能模量随着CaCO_3含量增加而下降。由于纳米填料较强的内聚能和较大的比表面积,FE-SEM发现存在部分刚性填料的集聚现象:且当CaCO_3含量超过临界值时,PVC涂层的不均质程度显著增加。从复数粘度分析可知,在较低频率时,改性PVC涂层呈现明显的宾汉塑性体流变特性;在高频时,其粘度与纳米填料含量呈反比。这些结果表明在纳米填料含量较高时,剪切有利于加速PVC大分子链的取向。

A series of polyvinyl chloride(PVC) coating modified by nano-CaCO_3 of about 100 nm were prepared and investigated.It is found that the viscosity of the PVC coating increases linearly with the increasing of thermal stabilizer Ba/Zn contents because of its greatly complex ability with the unstable Cl atom in PVC.The rheological results show that the storage modulus decreases when CaCO_3 content 510 wt%.Due to the strong cohesion energy and high specific surface area of the nano-CaCO_3,the non-rigid agglomerates formed by the fillers are observed and proved by the FE-SEM.When the CaCO_3 content is over a critical value,the degree of heterogeneity of the PVC coating significantly increases.For complex viscosities,the modified PVC coating notably exhibits the Bingham body flow behaviors at low frequencies,while the PVC nano-coatings show reversely proportion of viscosity to CaCO_3 content in the high frequency range.These results indicate that in the case of highly concentrated nano-fillers,a large amount of nano-fillers accelerate the orientation of the polymer chain under shear.