The Modification Of Ground Calcium Carbonate And Its Application In Polypropylene

Ground calcium carbonate has some advantages, such as cheap, non-toxic and odorless, good thermal stability and so on. It is one of the widely used inorganic filler. But the dispersion and affinity of ground calcium carbonate and PP is very poor, which would lead to the decrease of mechanical properties. So in order to broaden the application field, it is need to modified the surface of ground calcium carbonate.This article adopts the method of humidity modification in room temperature, make aluminate coupling agent DL–411 and sodium stearate as the modifier to modify ground calcium carbonate of 1250 mesh. In order to explore the best technological conditions, we test the performance of oil absorption value, sedimentation volume and contact angle. Fill the modified ground calcium carbonate in PP, and then test the mechanical properties, SEM, TGA, DSC of composite materials.(1)Prepared with low oil absorption values and sedimentation volume, high contact angle of the modified calcium carbonate. Compared to raw calcium carbonate, the oil absorption value and the sedimentation volume of aluminate coupling agent modified ground calcium carbonate reduced about 47.1 %, 45.8 %, and the contact Angle is 136.3 o, but the contact angle of literature is 120.0 o. The oil absorption value and the sedimentation volume of sodium stearate modified ground calcium carbonate is reduced about 50 %, the contact angle is 129.2 o, higher than the literature values which is 105.0 o.(2)The best filling quantity of sodium stearate modified calcium carbonate is 20 %. As compared with raw material PP, the impact strength increased by 15.7 %, the cost was reduced by 2300 yuan/ton. The best filling quantity of aluminate coupling agent modified calcium carbonate is 30 %, the impact strength increased by 16.0 %, the cost was reduced by 3500 yuan/ton. The improvement of the toughness of the composites are better than the raw material PP, and can save the cost.(3)When the content of aluminate coupling agent modified ground calcium carbonate is 40 %, adding 5 % toughening agent POE to have composite materials. As compare with the best filling quantity, it will save 1000 yuan/ton and the mechanical properties is almost the same. ?-polypropylene has such advantages, such as low elastic modulus, high impact strength and heat distortion temperature, but it is thermodynamically metastable, which is difficult to form. So add the ? crystal nucleating agent, and control the forming conditions, to get high content ?-PP and then to improve the performance of composite materials and reduce the cost of production.This article adopts the method of low energy humidity modification to prepare modified calcium carbonate with low oil value and sedimentation volume, high contact angle. And the modified effect is better than the literature value. Fill the modified calcium carbonate in PP to prepared composite materials, which can not only improve its toughness, but also can greatly reduce the cost.