Effect of binder on performance of intumescent coatings

This study investigates the role of the polymeric binder on the properties and performance of an intumescent coating. Waterborne resins of different types (vinylic, acrylic, and styrene-acrylic) were incorporated in an intumescent paint formulation, and characterized extensively in terms of thermal degradation behavior, intumescence thickness, and thermal insulation. Thermal microscopy images of charred foam development provided further information on the particular performance of each type of coating upon heating. The best foam expansion and heat protection results were obtained with the vinyl binders. Rheological measurements showed a complex evolution of the viscoelastic characteristics of the materials with temperature. As an example, the vinyl binders unexpectedly hardened significantly after thermal degradation. The values of storage moduli obtained at the onset of foam blowing (melamine decomposition) were used to explain different intumescence expansion behaviors.Funding for this work was provided by FCT-Fundacao para a Ciencia e Tecnologia (Project PTDC/EQU-EQU/65300/2006), and by FEDER/QREN (project RHED) in the - framework of Programa Operacional Factor de Competitividade-COMPETE. Joana Pimenta thanks FCT for PhD Grant SFRH/BDE/33431/2008

Influence of stereochemistry on cocrystallization in partially cycloaliphatic copolyamides

The aim of this work is to investigate whether or not both the cis and the trans isomers of either 1,4-cyclohexanedicarboxylic acid (1,4-CHDA) and 1,4-diaminocyclohexane (1,4-DACH) are participating in the formation of cryst. domains in copolyamides based thereon. Two isomeric series of partially cycloaliph. copolyamides were synthesized. In the series based on polyamide 12.6, the adipic acid residues were partially replaced by cis/trans mixts. of 1,4-CHDA, and in the series based on polyamide 4.14, the 1,4-diaminobutane residues were partially replaced by cis/trans mixts. of 1,4-DACH. By submitting these series of copolyamides to careful DSC and WAXS analyses, it could unambiguously be concluded that only the trans isomers of both 1,4-CHDA and 1,4-DACH residues are cocrystg. with the adipic acid based residues. Such evidence was not yet available in literature

Influence of stereochemistry on cocrystallization in partially cycloaliphatic copolyamides

The aim of this work is to investigate whether or not both the cis and the trans isomers of either 1,4-cyclohexanedicarboxylic acid (1,4-CHDA) and 1,4-diaminocyclohexane (1,4-DACH) are participating in the formation of cryst. domains in copolyamides based thereon. Two isomeric series of partially cycloaliph. copolyamides were synthesized. In the series based on polyamide 12.6, the adipic acid residues were partially replaced by cis/trans mixts. of 1,4-CHDA, and in the series based on polyamide 4.14, the 1,4-diaminobutane residues were partially replaced by cis/trans mixts. of 1,4-DACH. By submitting these series of copolyamides to careful DSC and WAXS analyses, it could unambiguously be concluded that only the trans isomers of both 1,4-CHDA and 1,4-DACH residues are cocrystg. with the adipic acid based residues. Such evidence was not yet available in literature. [on SciFinder (R)