Journal of Applied Polymer Science, Vol.129, No.6, 3333-3340, 2013
Synthesis and properties of novel alicyclic-functionalized polyimides prepared from natural -(D)-camphor
In this article, a new alicyclic-functionalized diamine, 1,3-bis(4-aminophenoxymethylene)-1,2,2-trimethylclopentane (BAMT) was successfully synthesized starting from natural (D)-camphor through four reaction steps of oxidation to offer a dicaboxylic acid, reduction to offer a diol, nucleophilic substitution to give a dinitro compound and then reduction to give the final diamine. Two alicyclic-containing polyimides were prepared by polycondensing BAMT with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) and 4,4-oxydiphthalicanhydride (ODPA), respectively. For the studies of the structure-property relationships of the polyimides, one aromatic polyimide of 4, 4-oxydianiline (ODA) polycondensed with ODPA was prepared in comparison. The alicyclic-containinig polyimides PI (BPDA-BAMT) and PI (ODPA-BAMT) maintain good thermal properties with glass transition temperatures (Tg) of 257 degrees C and 240 degrees C, and temperatures at 5% weight loss (T5) of 443 degrees C and 436 degrees C in nitrogen, respectively. The alicyclic polyimides exhibit tensile strengths of 91.9-133 MPa, Young's moduli of 2.753.24 GPa, and elongations at break of 5.6-18%. Compared with the aromatic polyimide PI (ODPA-ODA), PI (ODPA-BAMT) shows improved transparency with the UV-Vis transmittance at 500 nm over 80%. In addition, PI (ODPA-BAMT) displays better solubility than PI (ODPA-ODA), which has been confirmed by the bigger d-spacing value of PI (ODPA-BAMT) than that of PI (ODPA-ODA) calculated from the Wide-angle X-ray Diffraction spectra. This study indicates that the renewable forestry compound, such as natural (D)-camphor, could be a good origin for the structural designing and preparation of alicyclic-containing polyimides with outstanding combined features suitable for advanced microelectronic and optoelectronic applications. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013