Polypropylene nanocomposite fibers: A review of current trends and new developments

Abstract

In this review, traditional and novel techniques for producing micro- and nano- fibers are discussed and various nanofillers, their modifications and polypropylene (PP) functionalization routes are presented. Their influence on PP properties is discussed and new PP composite fiber applications are presented. This review reveals interesting conclusions, such as that in terms of mechanical reinforcement, there is no nano-filler that can improve tensile strength to the extent that it is improved by drawing. However, in some cases, composite drawn fibers are characterized by higher tensile strength than drawn neat PP. With some notable exceptions, the PP nanocomposites lack of “dramatic” properties improvement is mainly due to the non-polar nature of the hydrocarbon chain, which does not favor strong intermolecular interactions with most popular (mainly inorganic) nano-fillers. However, other properties such as electric conductivity, water contact angle and others can be effectively altered using various nanofillers in PP matrices.

Experimental Investigation of Polypropylene Composite Drawn Fibers with Talc, Wollastonite, Attapulgite and Single-Wall Carbon Nanotubes

“…Thermodynamically favorable polymer-additive interactions are commonly enhanced by the use of compatibilizers and/or appropriate modifications. Chemical modifications can be applied to the additive, to the polymer, or to both of them, in order to obtain optimum results [15].…”

“…Nevertheless, the grafting of PP with polar groups, such as maleic anhydride, results in more thermodynamically favored interactions with hydrophilic additives, such as montmorillonite (a phyllosilicate clay), which in turn may result in intercalated and/or exfoliated structures causing a significant improvement of composite properties [16]. Besides montmorillonite, several other reinforcement agents have been used, consisting of three main categories, i.e., mineral clays, carbonaceous fillers and other inorganic nanoparticles, which were recently reviewed [15]. Briefly, mineral clays that were used in PP composites include talc [17], boehmite [18], hectorite [19] and sepiolite, which present a needle-like morphology [20].…”

“…Since the mechanical properties of PP are significantly enhanced with drawing, further increase by the use of fillers in nanocomposite drawn fibers is a rather difficult task and less studied compared to PP non-drawn composites. In many cases, the deterioration of mechanical properties of PP fibers has been observed after the addition of fillers [15]. Probably, the poor interaction between PP and filler and the inevitable poor dispersion of particles disturbs chain alignment (that governs the increase in mechanical strength) during drawing.…”

“…On the contrary, proper treatment of fluorinated carbon nanotubes has been reported to cause a considerable improvement of mechanical strength, e.g., from 30.64 to 45.3 MPa using 2.5 wt.% carbon nanotubes, while the corresponding value for 10 wt.% carbon nanotubes was found equal to 77 MPa [31]. The use of various fillers in nanocomposite PP fibers was recently reviewed [15].…”

Tailoring the softness performance of polyethylene/polypropylene micro‐nanofibrous fabrics for skin contacts

“…PP is safe to use because it is lightweight (low-density), inexpensive, and has excellent chemical resistance. 3 Also, PP fabrics are commonly used as coverings that directly contact the human skin. 4 However, there is often skin discomfort caused by these PP coverings because the stiffness and insufficient flexibility of PP cause a foreign body sensation.…”