Preparation Of Calcium Carbonate Whisker For Epoxy Resin Usage,Its Surface Modification By Wet Modification And Influence On It's Mechanical Properties

Calcium carbonate is one of the important inorganic fillers.It is widely used in coatings,adhesives,aerospace,engineering plastics and other fields alcium.carbonate whiskers can not only reduce the cost of production,but also can improve the processing and comprehensive mechanical properties of materials.It will has extensive usage purpose in the future.In this study,uniform distribution of calcium carbonate whiskers with high aspect ratio was successfully prepared in novel batch reactor by optimizing the reaction conditions regulating,and the whiskers were surface modified by stearic acid and aluminate coupling agent,the modified whiskers were added to epoxy resin,and the influence of calcium carbonate whiskers to the mechanical properties of resin were studied.By using MgCl₂ as the crystal controlling agent,the effects such as initial concentration of Ca?OH?2 slurry,mechanical stirring rate,carbonization reaction temperature,magnesium calcium concentration ratio and C02 aeration rate on whisker synthesis was investigated.The results show that whisker calcium carbonate with a diameter ratio of about 25 can be prepared under conditions that C02 ventilation rate is 100mL·min-1 and mechanical stirring rate of 200 r·min-1,the control system of the carbonization reaction slurry concentration was 0.1mol·L-1 and magnesium calcium ion concentration ratio of 1.2 conditions.The appearance of calcium carbonate whisker is regular and the surface finish is high.The calcium carbonate whisker' were adjusted by wet modification using stearic acid and aluminate coupling agent as modifier.The effects of modifier dosage,modification time,modification temperature and mechanical stirring rate on the modification effect were investigated.The effect of modification was characterized by contact angle,activation index and oil absorption value.The results show that with conditions including the stearic acid at concentration of 4.5%?w/w?,modified temperature under 70 ?,the modification time of 30 min,the effect of mechanical stirring rate of 500 r·min-1 the optimum modification effect was obtained;as for aluminate coupling agent was used,the optimum conditions were changed to added in 3.5%agent,modified temperature under 90 ?,the modification time of 45 min and the mechanical stirring rate of 700 r·min-1.The contact angle is 141 degree while the calcium carbonate whisker modified by stearic acid and 122 degrees was presented while using aluminum acid ester of stearic acid.the FT-IR shows that calcium carbonate and the modifier molecules are combined with chemical bond,which is conducive to enhancing the fusion of calcium carbonate and organic matter and improve the mechanical properties of materials.The modified calcium carbonate whisker was added to epoxy resin to investigate the reinforcing effect of whisker added and the morphology of calcium carbonate.The results show that compared with the blank sample,as for calcium carbonate whisker stearic acid surface treatment,the tensile strength of the composite increased by 40.63%,the flexural strength increased 55.12%,compressive strength increased 43.75%,non-notched impact strength increased by 65.78%;while the aluminate calcium carbonate whisker surface treatment was presented,the tensile strength of the composite increased by 48.71%,the flexural strength increased by 53.10%,the compressive strength increased 51.55%,non-notched impact strength increased by 71.04%.The section SEM of epoxy resin composite which was added surface modification calcium carbonate are rough,and perplexing silver was observed on the surface,and obvious protrusions and displacement and large area plastic deformation can be seen in resin base,thus can absorb the impact energy massively,and strengthen the material flexibility.The calcium carbonate whisker prepared by this research can improve and mechanical properties of epoxy resin and other high polymer materials.It can be widely used in substitute of expensive SiC,titanium dioxide and other whisker materials,and has a good application prospect.