Surface Modification And Application Of Calcium Carbonate In The Polymers

Calcium carbonate?CaCO₃?possess extraordinary white degree,non-toxic,andgenerated product inexpensively in large quantities,making it to be an ideal candidates for a wide range of applications in areas of coatings,plastic,rubber,chemical fiber,adhesives,papermaking and so on.However,the addition of CaCO₃ to polymers does not always engender outstanding mechanical properties,and on the contrary,it has been reported to have deleterious effects in strength and toughness.This underperformance stems from several possible sources.Calcium carbonate has high surface energy,making it easy to aggregate and have weak interfacial bonding in the composites.Moreover,the smaller of calcium carbonate particle size,the more it is likely to aggregate.Therefore,in order to promote the application of calcium carbonate in the field of polymer,we have to improve its compatibility with polymer matrix.Surface modification is an established approach to overcome weak interfacial bonding in CaCO₃-reinforced composites.Adding the surface modification agent is a popular and effective method in improving composite properties on the industry.A lot of experiments on the surface modification of calcium carbonate with different particle size and its application in polymer matrix,including polypropylene?PP?,high density polyethylene?HDPE?,polyvinyl chloride?PVC?,and rubber,have been studied in this dissertation.First,the aluminate ester?411?-coated CaCO₃ particles with an average size of about 6.5?m were prepared by surface modification.The mechanical properties of modified CaCO₃ particles-reinforced PP were investigated.The results indicated that the tensile strength and impact strength of the composite PP/CaCO₃ was significantly improved,making it as an ideal candidates to be applied in the production of non-woven fabricsSecond,the aluminate ester?411?-coated CaCO₃ particles with an average size of about 5?m and 50 nm were prepared by surface modification.The mechanical properties of modified CaCO₃ particles-reinforced PVC were investigated.The results indicated that the tensile strength and impact strength of the composite PVC/CaCO₃ was significantly improved,making it as an ideal candidates to be applied in the production of rigid PVC products.Third,high density-polyethylene grafted with maleic anhydride-coated CaCO₃particles with an average size of about 6.5?m were prepared by surface modification.The mechanical properties of modified CaCO₃ particles-reinforced HDPE were investigated.The results indicated that the tensile strength and impact strength of the composite HDPE/CaCO₃ was significantly improved,realizing the application of calcium carbonate in HDPE containers.Finally,the aluminate ester?411?-coated CaCO₃ particles with an average size of about 5?m were prepared by surface modification.The mechanical properties of the modified CaCO₃ particles-reinforced styrene-butadiene rubber and natural rubber compound systems were investigated.The results indicated that the tensile strength and hardness of the composites were significantly improved,making it as an ideal candidates for the production of truck crawler.The results of this study indicate that,making a targeted surface treatment of CaCO₃ in view of the matrix resin performance and the requirements of product,and further through the gradation of different particle size of CaCO₃,which can significantly improve the compatibility of CaCO₃ with the matrix,resulting in the improvement of the composites comprehensive properties and significantly reducing the manufacturing cost of related products.