PU软段结构类型对PU改性沥青性能的影响

Effects of PU soft segment structure type on properties of PU modified asphalt

为探究聚氨酯(PU)改性沥青软段结构与其性能之间的关联性,促进PU改性沥青在实际道路工程中的应用,分别选用聚己二酸乙二醇酯二醇(PEA)、聚四亚甲基醚二醇(PTMEG)两种多元醇作为软段结构,以二苯基甲烷二异氰酸酯(MDI)和对二邻氯苯胺甲烷(MOCA)为硬段结构制备PU预聚体及PU改性沥青。采用针入度、软化点及延度试验观察不同软段结构对PU改性沥青物理性能的提升效果,并通过动态剪切流变(DSR)试验、弯曲流变仪(BBR)试验分析2种类型PU改性沥青的流变性能。借助红外光谱(FTIR)试验和差示扫描量热(DSC)试验,探究不同软段结构PU改性沥青性能的微观机理。结果表明:不同软段结构对PU改性沥青性能改善效果存在差异,其中,聚酯型多元醇PEA作为PU预聚体软段结构可有效改善PU改性沥青的高温性能,聚醚型多元醇PTMEG则对PU改性沥青的低温性能提升效果显著;对比2种PU改性沥青红外光谱,发现聚酯型PU改性沥青FTIR曲线中具有更高的酯基(—C=O)吸收峰峰值,而聚醚型PU改性沥青中醚基(C—O—C)吸收峰更显著,官能团的差异导致不同软段结构类型对PU改性沥青性能提升效果存在差异;此外,使用玻璃态转化温度T;衡量PU改性沥青低温性能时,使用聚醚型PU改性沥青低温性能优于聚酯型PU改性沥青。因此,在实际应用PU改性沥青时可根据性能要求选择相应的多元醇作为软段结构制备PU预聚体。

To study the relationship between soft segments of polyurethane(PU)and the properties of PU modified asphalt,and in order to promote the application of polyurethane modified asphalt in practical road engineering,two different types of polyols(poly ethylene-glycol-adipate(PEA),polytetrahydrofuran ether glycol(PTMEG))were used as soft segments,diphenylmethane diisocyanate(MDI)and P-(bi-O-chloroaniline)methane(MOCA)were used as hard segment to synthsis PU prepolymer and PU modified asphalt.The penetration,softening point and ductility were used to reflect the improvement effect of different soft segment structure types on the physical properties of PU modified asphalt.Dynamic shear rheological(DSR)test and bending beam rheometer(BBR)test were used to test the theological properties of PU modified asphalt.Meanwhile,Fourier transform infrared spectrometer(FTIR)test and differential scanning calorimetry(DSC)test were used to analyzed different soft segments effect on the modification mechanism of PU modified asphalt.The results show that different soft segments have different effects on the properties of PU modified asphalt.Polyester polyol PEA as soft segment of PU can effectively improve the high temperature performance of PU modified asphalt.Meanwhile,polyether polyol PTMEG as soft segment of PU can improve the low temperature performance of PU modified asphalt.By comparing the FTIR curves of two kinds of PU modified asphalt,it is found that the FTIR curve of polyester PU modified asphalt has a higher(—C=O)peak value,while the(C—O—C)peak value of polyether PU modified asphalt is more significant,the difference of functional groups leads to the difference effect of soft segment structure types in improving performance of PU-modified asphalt.In addition,when the low temperature performance of PU modified asphalt is measured by the glass transition temperature T;,it can be seen that the low temperature performance of the polyether type PU modified asphalt is better than that of the polyester type PU modified asphalt.So,in the practical application of PU modified asphalt,the corresponding polyols can be selected as soft segment structure to prepare PU prepolymers according to the performance requirements.2 tabs,11 figs,28 refs.