Synthesis And Application Of Biomass-based Polyester Polyol

Preparation of polyether polyol by catalytic liquefaction of biomass is an effective way to achieve efficient utilization of renewable resources. Polyether polyol is a key raw material for polyurethane foam and related material. This paper proposed a new process to prepare polyether polyol qualified for rigid PU foam production with corn starch as raw material by optimizing catalytic liquefaction process and optimum conditions, and the preparation of flame-retardant polyether polyols based on it.First, the solid sulfonic acid was prepared with ethylene tar as a raw material by polymerization, sulfonation and drying processes, and it is characterized by SEM, FT-IR, TG, TPD analysis to identified the structure and morphology. The results show that the particle size of the ethylene tar acid produced is of 10-30μm, mostly blocky morphology, the initial decomposition temperature of 300 oC and a medium–strength acid.Then, this ethylene tar acid is used in the starch liquefaction reaction, effects of reaction temperature, the ratio of raw materials, liquefaction time, liquefacant kinds and amount and catalyst dosage on the liquefication was investigated, and the optimal liquefaction conditions was determine as follows: temperature 150 oC, time 30 min, solid-liquid ratio of 1: 6, liquefied agent composition PEG200: glycerol of 7: 3, the catalyst was 3%(m), liquefaction conversion 95.6%, the products give a hydroxyl value of 235 mgKOH /g, viscosity of 376.5mPa.s, water content of 4.5% of polyether polyol. With catalyst repeated use of 20 times, liquefaction conversion can be maintained at more than 95 % to demonstrate excellent activity stability.The prepared liquefied polyol was successfully used to prepare a polyurethane rigid foam with density of 72 kg / m3, initial thermal decomposition temperature 250 oC, the average thermal conductivity of not more than 0.027 W / m ? K, to meet the national standards quality requirements of polyurethane insulation materials(GB10800-89).Then, the liquefied product was modified to improve its fire-resistant property with trimethyl phosphite(TMPP) and epichlorohydrin. The optimum conditions were as follows: reaction time 6h, temperature 160 oC, TMPP amount 10.0g, one-step foaming process was used for preparing flame-retardant polyurethane foam. The results show that the oxygen index increased from 21.75 to 27.15, showing the foam being hardly combustable.At last, The article also explores the waste foam recycling process by catalytic alcoholysis. The optimal condition was as follows: dibutyl tin as catalyst in an amount of 10%(m)and a temperature of 180 oC, 4 hours; waste polyurethane foam with an alcohol solution agent glycol ratio of 1: 1, the liquefaction conversion was 100%, It is identified that the alcololysis product was a mixture of polyether polyol and several aromatic amines, having a hydroxyl value of 546.3mgKOH / g, a viscosity of 100 mPa.s,which is applicable for PU rigid foam preparation.