Modification Of Conch Powder And Its Reinforcement On Composite

Conch is a kind of inexpensive and rich natural resources. How to make full use of shell resources has become a significant subject on recycling economy with the aim of reusing waste, causing much attention by researchers increasingly. It's well know that the shell is a natural organic-inorganic hybrid materials, with 95% of calcium carbonate and small amount of amino acids and sugars, which is called biological mineralization mechanism giving shell unparalleled strength and toughness. This topic attempts to make relevant discussion on surface modification process of shell powder as well as preparation of its composite material.The surface treatment of fine particles and its enhanced application on adhesive in bullet-proof UD plate was studied in this paper. Ultra high molecular weight polyethylene(UHMWPE) fiber was unidirectionally oriented and bond with thermoplastic resin PE to form UD plate, which is the world's strongest and lightest bullet-proof material. PE is the largest output of thermoplastic resin and widely used as pipe, film etc. However, because of its high crystallization, poor impact resistance and heat resistance, integrated mechanical strength of PE is is not good enough for bullet protection. Shell has a unique cross-layered structure which can improve the impact resistance of polyethylene composites; while the main component of shell powder CaCO3 can improve the heat resistance and anti-aging properties of polyethylene material. But Shell powder is a micron powder particles with large surface energy and easy to be agglomerated, and consequendly aggregated particles will affect the material impact performance due to stress concentration and rapid development of cracks. Therefore, shell powder should be treated to reduce the surface energy so that the shell powder in the matrix could achieve uniform dispersion.First in this study, shell powder was modified by different surfactants and coupling agents as well as different modification methods. Preferred modifiers were found by methods such as contact angle and activation degree determination. The results show that under the same conditions, the effect of coupling agent is better than that of surfactant. The effects of experimental conditions such as time, temperature on the modification of dry method by sodium stearate were studied. Taking titanate NDZ201 wetting modification for example, the optimum conditions of single factor are explored.4 factors and 3 levels orthogonal experiment is designed and carried out. Results showed that the optimal combination of shell powder modified by titanate NDZ201 is that the reaction temperature 60℃; reaction time 1.5h; coupling agent 2%; and thinner usage 1:2.The shell powder before and after modification were characterized by FTIR, DTG, SEM and other technical means. The mechanism of chemical modification by different modifiers is carefully studied. PE/shell powder composite material was carefully prepared by melt blending and injecting methods. After adding 5% shell powder with titanate NDZ201 treated under the optimum conditions to PE matrix, results showed that the elastic modulus of composite materials is 0.8GPa,rised by 15% compared with that of pure PE 0.69GPa;the tensile strength of composite materials is 23.96MPa,rised by 20% compared with that of pure PE 19.50MPa;the impact strength of composite materials is 5.6kJ/m2, rised by 10% compared with that of pure PE 5.1kJ/m2.. Finally, hydrophilic shell powder material with hydrophobic wall was made and tested their dispersion in the matrix.