Reaction Kinetics Of IPDI

The reaction kinetics of IPDI and n-butanol were studied by in situ FTIR. The influences of catalysts and the molar ratio of [NCO]/[OH] on the rate constant and the reaction selectivity of two NCO groups in IPDI was studied. The results indicated that the apparent reaction followed with the second-order reaction rule and sec-NCO groups of IPDI had higher reactivity than prim-NCO groups. When catalyst was used, the reaction rate and selectivity was markedly increased. Catalytic efficiency of catalyst in the reaction was followed:Zinc Octoate>Lead naphthenate>Stannous Octoate>without catalyst. The value of S with different catalyst was followed:Stannous Octoate>Lead naphthenate>Zinc Octoate>without catalyst. The influence of the molar ratio of [NCO]/[OH] on the rate constant and the reaction selectivity of [NCO] in IPDI was also obvious.The rate constant and S value with different the molar ratio of [NCO]/[OH] was followed: [NCO]/[OH]=2/1>[NCO]/[OH]=1/2>[NCO]/[OH]=1/1. The influence of temperature on the rate constant and reaction selectivity of IPDI was observed. With the increase of temperature, the reaction rate constant was increased, and S value was decreased.The reaction kinetics of IPDI and 2-butanol were studied by in situ FTIR. The results indicated that the apparent reaction followed with the second-order reaction rule. The reaction rate is increased with the increase of temperature, and without catalyst the Eaapp is 55.5kJ/mol. When catalyst was used, the reaction rate was markedly increased.The reaction rate constant with different catalyst (kapp) was followed:Zinc Octoate>Lead naphthenate> Stannous Octoate>without catalyst. The Eaapp with different catalyst was also followed: without catalyst>Stannous Octoate> Lead naphthenate>Zinc Octoate.Polyurethane (PU) elastomers based on IPDI were synthesized by one step method in which Zinc Octoate, Stannous Octoate, Lead naphthenate and Bismuth Octoate were used as catalysts.The relationship between the sort of catalysts and the structure, properties of elastomers was studied.The effects of the catalysts content were also studied.The result showed that the degree of separation of soft and hard domains of PU was obvious when Stannous Octoate was used. And the degree of separation of soft and hard segments of PU was decrease when Zinc Octoate was used. The tensile strength of PU is the highest when Bismuth Octoate was used,however the tensile strength of PU is the lowest when Stannous Octoate was used.The compatibility of soft and hard domains in the PU was increased with the increase of Stannous Octoate content in PU, which leads to the increase of mechanics properties.