Modification Of Nano-CaCO₃ And Its Application In Plastics

In view of the shortcomings of the unmodified nano-CaCO₃ in the application of plastics,such as easy agglomeration,poor dispersion and inferior compatibility,according to the recommended technical requirements of nano-CaCO₃ for rubber and plastics in GB/T 19590-2011,the surface modification of nano-CaCO₃,which was the self-made product of our laboratory,was carried out using fatty acid as modifier,and then the addition effect of modified nano-CaCO₃ on ABS and PP plastics was investigated.The main research work and conclusions are as follows:(1)DL-malic acid was screened as the more suitable modifier.The optimum modification conditions were determined as follows:DL-malic acid dosage 1.5%,modification temperature 60?,the ratio of solid to liquid 8:100,modification time120 min and stirring rate 300 rpm.The oil absorption value of the modified nano-CaCO₃ sample is 26.14 g·100g^-1,and all the other indexes meet or exceed the requirements of nano-CaCO₃ for rubber and plastics in GB/T19590-2011.(2)The addition effect of modified nano-CaCO₃ on the mechanical properties of ABS composites was investigated.The experimental results showed that when adding10%of modified nano-CaCO₃,the impact strength,elongation at break,tensile strength and bending strength of the modified nano-CaCO₃/ABS composites increased by 21.8%,30.28%,5%and 2.7%respectively,compared to that of pure ABS.The action mechanism of modified nano-CaCO₃ was preliminarily discussed as well.(3)The addition effect of modified nano-CaCO₃ on the mechanical properties of PP composites was investigated.The experimental results showed that when adding 10%of modified nano-CaCO₃,the impact strength and bending strength of the modified nano-CaCO₃/PP composites increased by 16.2%and 19.85%,compared to that of pure ABS.However,the elongation at break and tensile strength of the modified nano-CaCO₃/PP composites only decreased by 9.4%and 5.89%,respectively.The action mechanism of modified nano-CaCO₃ was preliminarily discussed as well.(4)The thermal stability analysis of the modified nano-CaCO₃/ABS and modified nano-CaCO₃/PP composites showed that the modified nano-CaCO₃ could inhibit the decomposition of both the ABS and PP composites and improve their thermal stability.(5)Analysis of the melt mass flow rate of modified nano-CaCO₃/ABS and modified nano-CaCO₃/PP composites showed that:when the addition of modified nano-CaCO₃ was less than 18%(for ABS)and 10%(for PP),the addition of modified nano-CaCO₃ could improve the melt mass flow rate,thus ameliorate the processing properties of the composites.