Surface Modification Of Mg₂B₂O₅ Whiskers And Tensile Properties Research Of MBOw/PVC

Mg2B2O5 whiskers(MBOw) were modified with borate and stearic acid via wet- modification method to improve the hydrophobic- lipophilic properties, and the optimum conditions for surface modification were also investigated by measuring the contact angles. Effects of modifier dosage, reaction temperature and reaction time were studied, and the best modification conditions were finally determined. The optimal modified conditions with borate are as follows: the dosage of borate, the reaction temperature and the reaction tim are 20%, 65 oC, 60 min, separately. While the dosage of stearic acid, the reaction temperature and reaction time are 6%, 65 oC, 60 min, separately. The results of Fourier Transform Infrared Spectroscopy(FT-IR) confirmed the existence of modifying agents on the surface of MBOw, which made it hydrophobic. The surface of MBOw becomes hydrophobic. XRD and SEM analysis results show that the crystal structure of magnesium borate whiskers were not changed by modified agent.The tensile properties of PVC were consolidated by adding of 5%~30% untreated/treated MBO w using solution blending method. The results show that the mechanical of composites are optimum when 20 % whiskers are added. The tensile strength and elastic modulus of unmodified MBO w composite increased by 38.1% and 76.2%, respectively, with respect to PVC resin. In addition, t he tensile strength and elastic modulus of borate treated MBOw composite increased by 62.7% and 93.9%, respectively. And the tensile strength and elastic modulus of stearic acid modified MBOw composite increased by 49.5% and 91.0%, respectively. The results of scanning electron microscop ies(SEM) show that the interface compatibility of treated MBOw/PVC composites is better than untreated MBOw /PVC composites.Polyvinyl chloride composite materials reinforced with Ca2B2O5·H2O(CaBOw), Cu2Al6B4O17(CuAlBOw), MgSO4·5Mg(OH)2·3H2O(MOSw), CaCO3 and CaSO4 whiskers are prepared by solution bending method to study the effect of different whiskers on PVC. The morphologies of samples after tensile tests were examined by a scanning electron microscope. The results show that except for MOS, the other whiskers have varied degrees enhancement effect on PVC. Among them, tensile properties of MBOw/PVC are best.