Effect of compatibilizer molecular weight and maleic anhydride content on interfacial adhesion of polypropylene-PA6 bicomponent fibers

The overall goal of the current research was to produce a bicomponent fiber consisting of a isotactic polypropylene sheath and a nylon-6 core that would be suitable for use in a pigmented carpeting application. To accomplish this, such bicomponent fibers were produced, and in situ reactive compatibilization was achieved using a maleic anhydride–functionalized polypropylene (PP–MA) at the interface. Bicomponent fibers with a side-by-side configuration were also spun as part of the investigative process. The adhesion of the materials at the interface and, therefore, the wear characteristics of the fibers were found to depend strongly on the molecular weight and the maleic anhydride content of the functionalized polypropylene. The wear properties and the quality of interfacial adhesion were characterized using optical microscopy to observe fiber cross sections and by accelerated wear testing of carpet samples. Differential scanning calorimetry, capillary rheometry, and tensile testing allowed for additional characterization of the materials in order to explain the differences noted in fiber performance.