三乙醇胺改性沙柳液化产物/异氰酸酯硬质泡沫材料研究

生物质多元醇液化产物与异氰酸酯等反应可制备硬质聚氨酯泡沫材料,而该类材料存在力学性能低、脆性大等缺点,使其应用领域受到限制。以沙柳多元醇液化产物为原料,与异氰酸酯(MDI)等共聚制备沙柳液化产物/异氰酸酯硬质泡沫材料(RPUF),研究添加不同质量分数交联剂三乙醇胺(TEOA)对RPUF物理力学、化学结构和热学特性的影响。结果表明:添加三乙醇胺可促进酯化反应生成更多的氨基甲酸酯基,并促进C=O分子链延伸振动。冲击强度和压缩强度随三乙醇胺添加量的增加呈先增大后减小的变化趋势,添加质量分数为2%时达到最大值,分别为2.36 MPa和1.78 kJ/m²,SEM表明此时泡孔形态较优;弯曲强度呈先减小后增大的变化趋势,添加质量分数为6%时最低为0.64 MPa,XRD表明此时结晶面积最大、结晶状态最好。RPUF为双阶段燃烧过程,添加三乙醇胺可提高该材料初始分解温度并增加残炭率,添加质量分数为2%时残炭率达到最高值38.99%,同时熄灭时间从202 s延长至248 s;添加三乙醇胺可延长热释放速率(HRR)第2次峰值时间,但总热释放量(THR)略有升高。三乙醇胺交联改性生物质基硬质聚氨酯泡沫材料添加量应控制在合理范围内。

Study on triethanolamine modified salix liquefaction/isocyanate rigid foam

The rigid polyurethane foam materials can be prepared by reaction of liquefied products of biomass polyols with isocyanates,which had the drawbacks of low mechanical properties and brittleness,limiting their application fields.In this study,Salix psammophila was used as the raw material,and the polyol liquefaction process was used to prepare the salix liquefaction product,which was then copolymerized with isocyanate(MDI)to prepare the salix liquefaction product/isocyanate rigid foam material(RPUF).The results showed that:1)The overall trends of the infrared spectrum before and after the modification of RPUF with triethanolamine were basically similar;the hydroxyl group in triethanolamine promoted the formation of the esterification reaction,while retaining the macromolecular structure represented by the hydroxyl group in the biomass raw material;the addition of triethanolamine promoted the esterification reaction to produce more carbamate groups,and promoted the extension vibration of C=O molecular chain.2)With the increased amount of triethanolamine,the compressive strength and impact strength of RPUF firstly increased and then decreased.When the amount of addition was 2%,the compressive strength and impact strength reached the maximum values,which were 2.36 MPa and 1.78 kJ/m²,respectively.Compared with pure RPUF,it was increased by 19.19%and 45.9%,respectively.According to the SEM images,it can be seen that the cell morphology was better and the cell rate was the largest;with the increase of triethanolamine,the bending strength of RPUF firstly decreased and then increased;when the addition amount was 6%,the bending strength was the lowest at 0.64 MPa,which was 70%lower than the control group;the XRD analysis showed that the crystalline area was the largest and the crystalline state was the best at this time.3)The combustion behavior of RPUF was a two-stage combustion process.The triethanolamine modified RPUF increased the initial decomposition temperature and increased the amount of carbon residual rate.When the amount of triethanolamine was 2%,the amount of carbon residual rate reached the highest value of 38.99%.Compared with the control group,it was increased by 89.64%,and the extinguishing time was extended from²02 to 248 s;when the addition amount of triethanolamine was 4%,the heat release rate(HRR)was at least 282.91 kW/m²;the heat release(THR)increased slightly.Therefore,the use of triethanolamine modified biomass-based rigid polyurethane foam should be controlled within a reasonable range.