Abstract
Hot-melt polyamides are an important market for the dimer acid made from the tall oil fatty acids liberated during the Kraft pulping process. These polyamides bond well to many substrates, but not to polyvinyl chloride (PVC), commonly called vinyl. Dimer-based polyamides made from secondary amines such as piperazine bond well to vinyl. No model for this unique adhesion has been proposed even though many commercial adhesives and other patents have utilized this feature of dimer-based polyamides. This paper examines the validity of models based on mechanical interlock, rheological properties, solubility parameters, and acid–base interactions. Available data are consistent with the acid–base model, which depends on the availability of tertiary amides made from secondary amine to bond to the vinyl hydrogen in contrast to the strong internal polyamide hydrogen bonding of secondary amides made from primary amines. Poly(ester-amides) with a similar proton acceptor ability also bond to vinyl.
Published Version
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