Preparation and properties of polyimide with a large volume aliphatic ring structure containing norbornene
A new type of diamine and dianhydride monomer containing a large volume aliphatic ring structural unit of norborn-ene were designed and synthesized by using norbornene as the raw material for the introduction of aliphatic ring structure,and the new hemicyclic polyimide materials PIA and PIB were prepared by polycondensation with traditional dianhydride and diamine,respectively.Fourier transform infrared spectroscopy,nuclear magnetic resonance spectrum were used for structural analysis.The results show that norbornene large-volume aliphatic ring structural units are successfully introduced into the traditional aromatic polyimide(PIC)molecular chain.At the same time,the effect of the introduction of large aliphatic ring structural units on the solubil-ity and hydrophobic properties of aromatic polyimide was tested,and the results show that the introduction of norbornene large-volume aliphatic ring structure can significantly enhance the solubility of traditional aromatic polyimide powder in common solvents,and at the same time can overcome the defect of high moisture absorption rate of thin-film material,and PIB is slightly lower than that of PIA on the moisture absorption rate,which are 0.77%and 0.82%,respectively,and much lower than that of PIC film(1.54%).The thermal stability test and the mechanical properties test show that the 5%thermal decomposition temperature(T5%)of PIA and PIB films are lower than that of the traditional PIC(560℃)with full aromatic structure,and the T5%of PIB(381℃)is lower than that of PIA(405℃).In addition,the tensile strength of PIA and PIB films are lower than the PIC film at room tempera-ture(25℃),which are 85 MPa and 79 MPa,respectively,but the elongation at break of PIA and PIB films are higher than the PIC(3.5%),which are 5.9%and 6.4%,respectively.While improving the solubility,processability and hydrophobicity of PI films,the thermal stability and mechanical properties can still meet the needs of some applications.
polyimidelarge volume lipid ring structureprocessabilitysolubilityhydrophobicity
NETL
NSTL
万方数据
