Extrusion and injection-molding of glass fiber/MAPP/polypropylene: effect of coupling agent on DSC, DMA, and mechanical properties

Abstract

Glass fiber-reinforced PP composites compatibilized with maleic anhydride grafted polypropylene (MAPP) were compounded with a twin-screw extruder and injection molded. The composite specimens were subjected to DSC, DMA, tensile, and flexural property characterizations. DSC results showed that the presence of glass fiber loading and MAPP produced insignificant effect on the melting temperature of the composites. The melting enthalpy was decreased with glass fiber loadings, but no significant change was noted in the crystalline peak temperatures (T c ). Incorporation of the compatibilizer led to a reduction in T c . Incorporation of glass fiber reduced the crystalline enthalpy of compatibilized and uncompatibilized systems. DMA results showed that composite properties were affected by the presence of the compatibilizer at low fiber loading ( 14% V f ). Tensile and flexural properties also showed sensible improvement of compatibilized against uncompatibilized composite systems.

Effect of compatibiliser on the properties of polypropylene/glass fibre/nanoclay composites

“…The dynamic storage modulus (Eʹ) is analogous to the flexural modulus measured as per ASTM D-790 standard [2,24,25] and closely related to the load bearing capacity of a material. with the relaxation of the amorphous phase.…”

“…The additions of 2, 5 and 8 wt% of MAPP into the composite further increased the Eʹ value to 6.90, 6.88 and 6.86 GPa, respectively (Figure 6b). An improvement in E' could be due to the enhancement in the interfacial adhesion between the GF and the PP by the presence of compatibiliser in the composite system [2] . Through microscopic studies, it can clearly be seen that in the compatibilised composite, some of the polymer matrix adhered to the GF surface indicating a good fibre-matrix adhesion (Figure 7a).…”

“…The " E T a values of the compatibilised composites shifted to higher temperature as compared to the uncompatibilised composite and PP matrix, which is probably due to restricted of the segmental motion in the amorphous PP chains at the fibre-matrix interface [31] . This suggests that the more restricted motion of the polymer molecules due to the increased fibre-matrix adhesion in the presence of MAPP resulted in less distinct and broader transition peaks [2] . The max E′′ value decreased generally with MAPP loading.…”

“…Generally, the compatibilised hybrid composites displayed improved Eʺ values throughout the experimental temperature range. The addition of 2 wt% of MAPP into PP/GF15/NC6 hybrid composite shifted the The ratio of the loss modulus to the storage modulus is measured as the damping factor or mechanical loss (tan δ) [2,12] . Since the damping peak occurred in the region of the glass transition where the material changed from a rigid to a more elastic state, it is associated with the movement of small groups and chains of molecules within the polymer structure [30] .…”

“…Polypropylene (PP), one of the most exploited thermoplastic resins in the composites, alloy and blends industries [1] , possesses outstanding properties like low density, good abrasion resistance and excellent electrical properties [2] . However, to cope with some limitations of PP, for example, low stiffness and low strength, and to expand their applications in different sectors, inorganic fillers, such as glass fibre (GF), carbon nanotubes and clays, are often added when processing the polymer composites, which normally combine the advantages of their constituent phases [3] .…”