Research On Surface Modification Of Calcium Sulfate Whisker By Gas Floating Technology

Calcium Sulfate Whisker is a micro size single crystal fiber material,which is widely used in the friction material,environmental protection,plastic,asphalt,rubber,adhesives,paper making,and other industries.While,the surface of calcium sulfate whisker has strong polarity,high surface energy,and its character differs from organic matrix that it cannot tolerant with the organic matrix.So the surface modification of calcium sulfate whisker is needed,improving its hydrophobicity,lowering surface energy and enhancing the compatibility with organic matrix,improving the dispersion in organic matrix,then meeting the requirements of modern new material and new technology.This paper breaks the traditional wet modification methods,innovatively using gas floating modification technology to modified surface of calcium sulfate whisker.The paper develops new type of modified agent,researching the calcium sulfate whisker surface modification mechanism and provide reference for other inorganic mineral filler surface modification.At first,this paper used several kinds of common modifier in laboratory to modify calcium sulfate whisker with floating modification.Then the sodium stearate was selected relatively good modifier for the modification effect.The sodium stearate was used for condition of single factor experiment to modify calcium sulfate whisker by gas floating.The result:when the dosage of modifier was 10%,slurry concentration was 5%,slurry pH was 8?10,modification temperature was 45 ?,the stirring speed was 1000 r/min,modification time was 20 min and baking temperature was 80?,it can got yield 45.62%,activation index 100%,contact angle 108.50 ° and oil absorption value 29.43 modified product.Secondly,in view of the dosage of sodium stearate was excessive and the problem of low yield,several kinds of modifier synthesized by oneself in laboratory were used to modify calcium sulfate whisker by the gas floating modification.The experimental results:DZY-5 and DZY-6 modifier were chose as the best modifier.Modifier DZY-5 and DZY-6 were used to modify calcium sulfate whisker by gas floating modification for single factor experiment.The results of DZY-5 modifier modifying calcium sulfate whisker:under the condition of modifier dosage of 2%,slurry concentration 5%,pH 12,modification temperature 45?,stirring speed 1000 r/min,drying temperature 80?,modification time 35 min,it can obtained yield 96.36%,activation index 97.64%,contact angle 102.00°,oil absorption value 24.22 calcium sulfate whisker modified products.The effects of DZY-6 modifier modifying calcium sulfate whisker:under the conditibn of modifier dosage 3%,slurry concentration 5%,pH 11,modification temperature 15?,stirring speed 800 r/min,drying temperature 80?,modification time 20 min,it can got yield 98.36%,activation index 99.50%,contact angle 115.00 °,oil absorption value 22.28 of calcium sulfate whisker modified products.By means of SEM and EDS spectrum,Zeta potential and FTIR etc modern technology and test results,the function of new modifier DZY-5 and DZY-6 between calcium sulfate whisker had been analyzed.The research showed that new modifier DZY-5 and DZY-6 mainly took effect chemical adsorption and weak hydrogen bonding interaction on calcium sulfate whisker surface.In this paper,the gas floating modification process feasibility was analyzed.Cafcium sulfate whisker morphology was observed by biological microscopeafter after modified by the gas floating modification technology.It found that the modified whisker hadnot fracture phenomenon within the scope of the stirring speed,ensuring the whisker original length-diameter ratio.Finally,the modified calcium sulfate whisker was added to the alkyd resin coatings,examining the calcium sulfate whisker effecting on the performance of the composite coating film.The results showed that the calcium sulfate whisker coud significantly shorten the film drying time,and calcium sulfate whisker had extinction effect to the coating.When the modified calcium sulfate whisker content was 10%,could improve the impact resistance,adhesion and flexibility of coating film.This study has innovation on surface modification of calcium sulfate whisker,and can play a role in industrial production;At the same time,the calcium sulfate whisker applies in alkyd resin coatings research,extending the application of calcium sulfate whisker.