MICRO-PHASE SAEPARATION IN EPOXY RESIN WATERBORNE PARTICLES DURING CURING PROCESS

Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.     

EFFECT OF STRESS-INDUCED REACTIONS ON MORPHOLOGICAL STRUCTURE AND PROCESSABILITY OF PVC DURING PAN-MILLING

The effect of pan-milling on morphological structure, processability and properties of PVC was studied through SEM, FTIR, granulometer, GPC and mechanical properties test in the hope of gaining ease in operation, needless of plasticizers, a clean and efficient route for improving the processability of PVC through stress-induced reactions,fulfilling the idea of “plasticizing PVC by itself”. The experimental results show that during pan-milling at ambient temperature, within 2-3 min, the microcrystalline structure of PVC becomes indistinct, the grain size of PVC is reducedfrom 130-160 μm to 1-50 μm the molecular weight of PVC is slightly decreased, the variation of molecular weight distribution is indistinct, the plasticizing time and torque at balance drop a great deal from 71-132 s to 31-33 s and from 18.2-22.1 Nm to 14.7-18.4 Nm, respectively, the processability of PVC is markedly improved, and the mechanical properties get enhanced too.