Preparation Of Polystyrene-based Microspheres And Its Applications In Catalytic Reactions And Composite Materials

Polystyrene-based polymer microspheres have great application prospects in many technical fields due to their physical and chemical characteristics.Therefore,its preparation and application have attracted general interests in the field of materials research.Sulfonated polystyrene microspheres are an important variety in polystyrene-based microspheres.The preparation method is mainly to modify the surface of polystyrene microspheres by adding concentrated sulfuric acid or other sulfates.The use of concentrated sulfuric acid can cause equipment corrosion and environmental pollution,and the sulfonic acid group is only present on the surface of the microsphere after sulfonation,and the amount of sulfonate groups is difficult to control.In this paper,calcium carbonate was used as the carrier and its surface was chemically-modified by vinyl benzene sulfonic acid,and then the surface of the modified calcium carbonate was crosslinked with styrene,divinylbenzene and BPO to obtain polystyrene-based calcium carbonate microparticles balls.The polystyrene-coated calcium carbonate microspheres are acidified to obtain sulfonated polystyrene hollow microspheres(SPS-HMs);the polystyrene-based coated calcium carbonate microspheres are carbonized at medium temperature to obtain carbonized sulfonated polystyrene solid microspheres(CSPS-SMs).This work has been carried out based on the catalytical properties and reinforcement in composite materials of SPS-HMs and CSPS-SMs:1.Preparation of polystyrene-based microspheres(1)SPS-HMs:firstly modifying the calcium carbonate with p-vinylbenzenesulfonic acid,then adding styrene,divinylbenzene and free radical initiator to cross-link the surface of the modified calcium carbonate to obtain the product,then using concentrated hydrochloric acid acidified it to obtain functional sulfonated hollow microspheres,and its structure and properties are tested and analyzed.The results of optical microscopy and SEM showed that the shape of the polystyrene-based coating material was spherical or nearly spherical.The results of IR,XPS and EDX analysis indicated that the sulfonic acid group of the polystyrene-based microspheres was on the inner surface of the sphere.(2)CSPS-SMs:firstly modify the calcium carbonate with p-vinylbenzenesulfonic acid,then add styrene,divinylbenzene and a free radical initiator to cross-link the surface of the modified calcium carbonate to obtain the product.Then n the atmosphere of nitrogen,the process is raised and carbonized for 14 hours carried out to obtain polystyrene-coated calcium carbonate carbonized microspheres ball.OM and SEM test results show that the shape of polystyrene carbonized material is spherical or nearly spherical;IR analysis shows that CSPS-SMs contain sulfonic acid group and vinyl functional group;XPS and EDX test show that CSPS-SMs no sulfonic acid group was found on the outer surface,and its sulfonic acid group was found in the infrared spectrum,whereby the sulfonic acid group was on the inner surface of the microsphere.2.Application of SPS-HMs in organic catalysis(1)Using SPS-HMs as catalysts in the reaction of cyclohexanone with ethylene glycol ketal,the effects of catalyst dosage,reaction temperature,reaction time,material ratio and frequency of reuse on its yield were investigated.The study found that when the amount of catalyst is 0.5%(quantum ketone mass),the reaction time is 2 h,the ratio of cyclohexanone to ethylene glycol 1:1.2,and the reaction temperature is 100℃,the conversion rate reached 99.9%.It has high catalytic efficiency and stable catalytic performance with commonly used ketal catalysts.(2)Using SPS-HMs as the hydrolysis catalyst of macromolecular gallic acid tannic acid,the problems of catalyst dosage,reaction temperature,reaction time,material ratio and number of times of reuse were studied.The experimental results showed that the amount of catalyst is 7%(measured by tannic acid mass),the reaction time is 6 h,the reaction temperature is 80℃,and the material ratio is 1:3,the yield of gallic acid can reach 96.99%.Compared with the currently used catalysts,the yields obtained are higher and the wastewater discharge is less.3.The application of CSPS-SMs in composite materials(1)The CSPS-SMs/PA66 composites were prepared by melt blending with CSPS-SMs and PA66 as raw materials,and the structure and properties of the composites were studied.The TGA test results show that CSPS-SMs/PA66 composites have good thermal degradation stability.The results of IR analysis show that CSPS-SMs interact with PA66 during blending and extrusion;DSC,DMA,thermal deformation and Vicat softening point temperature measurement showed that the melting temperature,crystallization temperature,storage modulus,glass transition temperature,thermal deformation and Vicat softening point temperature of CSPS-SMs/PA66 composites were higher than that of pure PA66.The results of mechanical properties analysis showed that the tensile strength,impact strength,flexural strength and elastic modulus of the carbonized CSPS-SMs/PA66 composites compared with pure PA66 when the amount of CSPS-SMs was 5 phr increased by 13.88 MPa,1.02 kJ/m2,7.4 MPa,0.24 GPa;SEM impact section analysis showed that the compatibility of spherical surface and matrix interface in CSPS-SMs/PA66 composites was good.(2)CSPS-SMs/PC composites were prepared by melt blending with CSPS-SMs and PC as raw materials,and the mechanical properties of the composites were studied.The results of SEM impact section analysis showed that CSPS-SMs/PC composites were compared with stearic acid,aluminate and titanate modified calcium carbonate/PC composites,and the particles were evenly dispersed without pores and particle shedding.The results of mechanical properties show that the tensile strength and flexural strength of CSPS-SMs/PC composites increase first and then decrease with the increase of CSPS-SMs.When adding 3 phr CSPS-SMs,compared with other PC modified composites modified with calcium carbonate,the tensile strength,flexural strength and elastic modulus of PC composites increased significantly.(3)CSPS-SMs/NBR composites were prepared by open-mixer wet mixing method.The experimental results of the rotorless vulcanizer show that with the increase of CSPS-SMs,the minimum torque,maximum torque and torque difference of CSPS-SMs/NBR composites increase first and then decrease.The results of crosslink density analysis showed that the crosslink density of CSPS-SMs/NBR composites increased with the increase of CSPS-SMs.The experimental results of mechanical properties show that the mechanical properties of the CSPS-SMs/NBR composites prepared by the wet mixing method are better than those of the dry mixing method.With the increase of the amount of CSPS-SMs,the tensile strength and elongation at break of CSPS-SMs/NBR composites increased first and then decreased,and the tensile stress of 300%increased.When the amount of acid was 5%and the amount of CSPS-SMs was 100 phr,the tensile strength and elongation at break of CSPS-SMs/NBR composites increased by 213.6%and 170.9%,respectively,compared with pure NBR.The results of SEM impact section analysis show that CSPS-SMs/NBR composites have uniform particle dispersion and no pores and particle shedding.