Research On Preparation Of Hollow Highly Oil Absorption Resin With Micro/Nano-structures By Spray Drying

The presence of oil absorption materials was useful for resolving the pollution problem of oil leakage to environment. However, it is usually associated with several problems including water absorption and oil leakage under pressure. In this study, we used a new method spray drying to prepare Poly(styrene-stearic methacrylate) [P(St-SMA)] absorbent resin with micro/nano hollow structure. The proposed method was simple, economical, and the products had high oil absorption ability. On the other hand, spray drying which provided a new efficiency method to solve environment pollution, had potential study and application values.(1) Study of preparation and formation mechanism of hollow highly oil absorption resin with micro/nano-structure.The high oil absorption resins were synthesized by two-step polymerization in combination with spray drying, using styrene (St) and stearic methacrylate (SMA) as monomer, DCPMA as crosslinker. From scanning electron microscope (SEM) graphs, we found that the large hollow micrometer-sized spheres, prepared via spray drying, were aggregated by nanoparticles. Fourier transform infrared spectroscopy (FTIR) test showed that the resin included the characteristic function groups of P(St-SMA). The contact angle data of the resin by water was 111.14°and the surface free energy was 38.10 mJ/m2. On the first studying, the absorption ability for toluene could reach 20.78 g/g, the saturation time was 4 h. The resin exhibited excellent oil absorption and hydrophobicity. From the analysis of formation mechanism, we found that oligomer and spray drying were the effective conditions for preparing micro/nano hollow microspheres.(2) The effects of monomer ratio, oligomer molecular weight, crosslinker and emulsifier as well as porogen content on the microsphere morphology of the resin were investigated. It showed that only when the molecular weight of oligomer was moderate, hollow microspheres could be obtained. Only dendritic structure was formed when using styrene completely, and if styrene content was too low, micospheres adhered together. With the increase of the crosslinker content, microspheres were better formed, but the increase of porogen microspheres collapsed. When the content of emulsifier was too high or too low, the hollow structure could not be formed. The appropriate conditions were given as follows: oligomer molecular weight M n(2889～15099), St (33 wt%～80 wt%), DCPMA(≥1 wt%), emulsifier SDS:OP-10 = 2:1 (2 wt%～4 wt%), isopropanol porogen(10 wt%～40 wt%).(3) Particle size and its distribution of the oil absorption resin were studied and the result showed that particle size was small and had narrow size distribution. With the increase of emulsifier content, particles became smaller and particle size distribution broadened. When the initiator content rose, particle size decreased. The monomer ratio had certain effects on particle size, as the proportion of SMA grew, particle size first increased then decreased, and the increase of oligomer molecular weight and crosslinker as well as porogen had the similar change pattern. The appropriate conditions were presented as follows: oligomer molecular weight M n(10192～21603), St (25 wt%～75 wt%), DCPMA(1 wt%～5 wt%), SDS:OP-10 = 2:1 (2 wt%～4 wt%), porogen(10 wt%～40 wt%), KPS(2 wt%～4 wt%).(4) The best oil absorbency of the resin prepared by spray drying could reach 38.3 g/g. Mechanical and thermal properties were discussed. The results indicated that many parameters influence oil absorbency, and the recipe was optimized as follows: oligomer molecular weight: oligomer molecular weight M n = 15099, St = 67 wt%, 3 wt% DCPMA, 3 wt% emulsifier SDS:OP-10 = 2:1, 31 wt% porogen and 3 wt% KPS. The conditions were just in the range of conditions for preparing hollow structure and moderate size of microspheres, which showed that hollow structure and moderate size were the effective conditions for better oil absorption of microspheres.(5) Under the same conditions, the comparation between two-step polymerization-spray drying and suspension polymerization on oil absorption properties were investigated. It was found that the resin prepared by two-step polymerization-spray drying exhibited better oil absorption properties. The absorption ability and saturation time for toluene of the resin prepared by two-step polymerization-spray drying could reach 38.3 g/g and 4 h respectively, while those of the resin synthesized by suspension polymerization could reach 11.26 g/g,12 h respectively.