Novel Polyphosphonic Hydrazides as Potential Flame Retardent Additives for Polypropylenes

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Low temperature suspension polycondensation of phosphonic dihydrazide (PDH) with a series of aliphatic diacid chlorides: [CH2]n(COC1)2 n = 2,4,6 in dry N, N- Dimethylacetamide (DMAC) at -10°C afforded linear soluble & fusible polyphosphonic hydrazides (PPHs). Oxidative TG-DTA indicate their ranges for Mpt. 350-370°C corresponding to calculated Tg. 233.3-246.6°C. At first stage decomposition, their Ea and order of degradation evaluated were 1.69-2.58 Kcal mol-1 and 0.5-0.12 respectively. End group analysis indicate their Mn: 2.86-5.89 x 104. Inherent voscosities 0.24-0.47 dl gr-1 at 25 ± 0.1°C . All such PPHs have shown characteristics IR (KBr) frequencies in the range of vNH: 3300-3200cm-1 ,8 H-P = O; 800cm-1 and vP=0,1225cm-1. Various thermal, spectral and other analytical data evaluated indicate that the proposed PPHs are being associated with appreciable thermal and mechanical stabilities therefore, may be potentially required as a Heine retardant additives for polypropylenes.

polycondensation; phosphonic; dihydrazide Dimethylacetamide