Research And Development Of High Impact PVC Pipe Material With High Impact Resistance

PVC is widely used in the manufacture of plastic pipes due to its high mechanical strength,but its toughness is poor,results in easy cracking when subjected to strong impact,thus improving the impact performance of PVC,thereby endowing PVC pipes of excellent toughness is of great significance.In this paper,PVC/Ca CO₃/OMMT composites were prepared by melt blending,which could enhance and toughen PVC at the same time.Firstly,PVC/Ca CO₃ composites were prepared,and the best amount and type of calcium carbonate was determined;Secondly,we studied the impact of different content of CPE and B-20 on the mechanical properties of composites;then montmorillonite was added and the composite were further strengthened;Finally,PVC/Ca CO₃ composites and PVC/OMMT composites were alternately placed and then pressed to obtain alternate layered PVC/Ca CO₃/OMMT composites,and the effect of montmorillonite content on the properties of the composites were studied.We can draw the following conclusions:(1)The effect of the type and content of calcium carbonate on the properties of PVC/Ca CO₃ composites were studied.The results showed that the composites possess better comprehensive properties which with calcium carbonate modified by stearic acid and titanate coupling agent.Compared to its counterpart with unmodified calcium carbonate,its impact strength was increased by 15%;Five kinds of calcium carbonate had little effect on the glass transition temperature of the composites;And the two kinds of calcium carbonate with the best hydrophobicity had better dispersion in the system.(2)When CPE and B-20 were added with different contents,the impact strength of the composites increased,which from 3.351KJ/m~2 to 4.572 KJ/m~2 and 4.256 KJ/m~2 respectively,similar trend could be seen in the elongations at break of the composites;However,the tensile strength and bending strength of the composites decreased;In addition,the glass transition temperature of the composites changed little with the increase of B-20,but gradually slowed down with the addition of CPE;After adding CPE and B-20,the fracture surface of the composites became rough.(3)In order to further improve the tensile strength of the composites,different kinds of montmorillonite were added,and the tensile strength were enhanced by 10%as expected.The XRD analysis showed that,the larger the layer spacing of montmorillonite was,the better intercalation of PVC molecular chain were,and a partially exfoliated structure were formed.Like calcium carbonate,different kinds of montmorillonite had little effect on the glass transition temperature of the composites.(4)Only the tensile strength of the PVC/Ca CO₃/OMMT composites obtained with alternate layered structure was slightly increased,other performance were deteriorated;With the increase of the content of montmorillonite,the glass transition temperature of the composites increased slightly;However,the fracture surface of the composites became smooth,showing a brittle fracture.