Part Ⅰ : Synthesis and characterization of polyimides from unsymmetrical diamine with cyano group

Abstract

A new diamine monomer containing cyano group, 2-cyano-4,4``-diaminophenyl ether, was synthesized and polymerized to polyimides with several aromatic anhydrides via two kinds of imidization methods, namely, thermal or solution imidization methods. By the thermal imidization method, tough, flexible and creasable polyimide films were obtained, except the polyimide from pyromellitic dianhydride. The polyimides had high $T_g$ values and they are stable up to 500℃ in air. The polyimides prepared by solution imidization method are partially soluble in polar aprotic solvent with heating, but the reprecipitated polymer after dissolved in concentrated $H_2SO_4$ were well dissolved in polar aprotic solvents. Four kinds of core molecules, which have tetra- or octa-hydroxyl functional group, were synthesized from bisphenol A, 4,4``-biphenol and hydroquinone. These cores and neopentyl glycol were used as an initiator for the stannous octoate catalyzed living ring opening polymerization, and linear and star poly(e-caprolactone)s were synthesized. The linear polymer is more viscous than star polymers with similar molecular weights. Melting points of the polymers decreased with the increasing number of arms and decreasing DP. The 10% weight loss temperature is dependent on molecular weight but not on the number of arms. N,N-Substituted acrylamides including N-acryloylpiperidine (N-AP), N-phenyl acrylamide (PAA), and N-methyl-N-phenyl acrylamide (MPAA) were polymerized in various conditions using trialkylaluminums. N,N-Substituted acrylamide monomers were prepared from acryloyl chloride with piperidine, aniline and N-methylaniline, respectively. Polymerization of N,N-substituted acrylamides is faster at high temperature than at low temperature, except PAA. The molecular weights of the polymers initiated by triethylaluminum are higher than those of the polymers initiated by tyriisobutylaluminum.