液化稻殼為基質聚胺基甲酸酯之醇解產物再製PU發泡體性質之研究

Study on the Properties of PU Foams Reproduced from Glycolysis Products of Liquefied Rice Husk-based Polyurethane Resins

研究將多元醇液化稻殼與4, 4-二苯甲烷二異氰酸酯之寡聚物（PMDI）反應製造聚胺基甲酸酯樹脂（Polyurethane；PU）發泡體，並將此發泡體以二乙二醇／二乙醇胺混合液為共溶劑在190℃加熱100min進行醇解反應，所得醇解產物具備弱鹼性、低粘度、高羥價之特性。此醇解產物與液化稻殼或聚乙二醇（PEG-400）以重量比100／0、75／25、50／50、25／70及0／100混合後與異氰酸酯Desmodur N反應再製成PU樹脂，然單獨採用醇解產物為原料者（100／0）其發泡效果較低，而醇解產物／原生多元醇混合比50／50時，其發泡體性質與完全採用原生多元醇者（0／100）相似。各不同組成條件PU發泡體具有相同之熱裂解行為，其熱裂解反應主要發生在約230-420℃之間，由其重量損失可將熱裂解區分為四個階段，其中以第II階段具有較大之重量損失，其熱裂解發生溫度受反應物之架橋程度所影響，而熱裂解重量損失則受組成分所影響；添加原生多元醇可提高其熱裂解發生溫度，但第II階段之熱裂解重量損失則增大。 Glycolysis of polyurethane (PU) foams, made from reacting polyol-liquefied rice husk with polymeric 4,4'-diphenylmethane diisocyanate (PMDI), was carried out with diethyene glycol/ diethnol amine cosolvent at 190°C for 90 min. The product of glycolysis had the characteristics of weakly alkaline, low viscosity and high hydroxyl value. This glycolysis product was blended with original liquefied rice husk or polyethylene glycol (PEG-400) by the weight ratios of 100/0, 75/25, 50/50, 25/70 and 0/100 to reproduce PU resins by reacting with isocyanate (Desmodur N). The results showed that it had low foaming capability when only glycolysis product was used as the raw material (100/0) for PU foams manufacturing. But blending the glycolysis product with original polyols with the weight ratio of 50/50, the PU foams had the properties similar to that made from original polyols (0/100). All PU foams had a similar thermo-degradation behavior, although they were prepared with various compositions, which occurred predominant at the temperature between 230°C and 420°C and which could be separated into four stages according to their weight loss. Among which, the secondary stage of thermo-degradation had the most amount of weight loss, its onset temperature and weight loss were influenced by the cross-linking degree and the composing component, respectively. Mixing the glycolysis product with original polyols could raise the thermo-degradation temperature of the PU foams, but the weight loss at the secondary stage of thermo-degradation would be increased.

Glycolysis of polyurethane (PU) foams, made from reacting polyol-liquefied rice husk with polymeric 4,4'-diphenylmethane diisocyanate (PMDI), was carried out with diethyene glycol/ diethnol amine cosolvent at 190°C for 90 min. The product of glycolysis had the characteristics of weakly alkaline, low viscosity and high hydroxyl value. This glycolysis product was blended with original liquefied rice husk or polyethylene glycol (PEG-400) by the weight ratios of 100/0, 75/25, 50/50, 25/70 and 0/100 to reproduce PU resins by reacting with isocyanate (Desmodur N). The results showed that it had low foaming capability when only glycolysis product was used as the raw material (100/0) for PU foams manufacturing. But blending the glycolysis product with original polyols with the weight ratio of 50/50, the PU foams had the properties similar to that made from original polyols (0/100). All PU foams had a similar thermo-degradation behavior, although they were prepared with various compositions, which occurred predominant at the temperature between 230°C and 420°C and which could be separated into four stages according to their weight loss. Among which, the secondary stage of thermo-degradation had the most amount of weight loss, its onset temperature and weight loss were influenced by the cross-linking degree and the composing component, respectively. Mixing the glycolysis product with original polyols could raise the thermo-degradation temperature of the PU foams, but the weight loss at the secondary stage of thermo-degradation would be increased.