Abstract
New poly(N-benzoyl-4-(N-itaconimido)-benzhydrazide) (PBIBH) and a series of its metal complexes (PBIBH-metal complexes) have been prepared. The metals incorporated into the complexes involve Mn, Co, Ni, and Cu. Several analytical techniques such as elemental analysis, FTIR, H-1-NMR and electronic spectroscopy, magnetic moment and molar conductance were employed for proving their structures. PBIBH-metal complexes showed a greater activity than that of PBIBH against E. faecalis, S. epidermidis, P. aeruginosa and E. coli bacteria and against A. niger, C. neoformans, C. tropicalis and S. racemosum fungi. This was clarified from their higher inhibition zone diameters and their lower minimum inhibitory concentrations. The metal type in the complexes has a remarkable effect on their antimicrobial activity and its effect could be arranged as follows: Co > Cu > Mn > Ni. PBIBH-Co(II) complex displayed a greater potency than the used standard drugs in inhibition of growth of most of the tested microbes. Moreover, PBIBH and its metal complexes showed a higher thermal stabilization efficiency for PVC, relative to cadmium-barium-zinc (Cd-Ba-Zn) stearate, n-octyltin mercaptide (n-OTM) and dibasic lead carbonate (DBLC) industrial reference stabilizers, in terms of the increase in the initial decomposition temperature, the decrease in the weight loss at a particular temperature and the reduction in the discoloration degree. The good antimicrobial properties and high thermal characteristics of PBIBH and its metal complexes have afforded them great possibility to be used as biomedical additives for thermal stabilization of PVC.