Fiber preparation and mechanical properties of recycled polypropylene for reinforcing concrete

Polypropylene (PP) fibers have been widely used to reinforce concrete footpatbs as an alternative to steel mesh. The rein-forcing effect of the PP fiber is directly proportional to its tensile strength and Young modulus. This research explored the feasibility of using an improved it spinning and at drawing process to produce virgin and recycled PP fibers of high mechanical properties in an industrial scale. Commercial grade granules of virgin PP, recycled PP and HPDE were mixed in different proportions in preparing five different types of fibers. All the fibers obtained high tensile strength and Young modulus,. A relationship between the structural parameters and mechanical properties was then established. It was observed that the melt spinning and hot drawing process formed both alpha-form and beta-form crystals in the PP fibers, and significantly improved crystallinity from about 50% to 80%, (C) 2015 Wiley Periodicals, Inc.