Steady‐State and dynamic properties of concentrated fiber‐filled thermoplastics

Abstract

Rheometric data for short‐fiber‐filled thermoplastics are presented using a parallel‐plate viscometer. Polypropylene tensile bars contain short and long fibers with glass weight percentages of 0%, 5%, 10%, 20%, and 30%, polycarbonate tensile bars with glass percentages of 0%, 5%, and 10% long fibers, and nylon 6/6 tensile bars with 0%, 15%, 30%, and 45% short fibers. The short fibers were initially 3 mm in length and 12.7 microns in diameter. The long fibers were initially 6 mm in length and 10 microns in diameter. In the steady‐state experiments, the fibers increase the viscous stresses and the normal stresses in proportion to the concentration of fibers. At low shear rates, the viscosity is increased by the addition of the fibers, but at high shear rates the viscosity approaches that of the neat resin. In dynamic testing, the fibers increase the viscous and elastic components as measured by the complex viscosity and modulus. The fibers increase the viscous and elastic nature of the fiber‐filled composite at low frequencies and to a lesser extent at higher frequencies. The fibers increase the elastic component more than the viscous component at low frequencies and less at higher frequencies as demonstrated by tan δ.

Effect of fiber length on thermomechanical properties of short carbon fiber reinforced polypropylene composites

“…It indicates the viscous nature of the polymer [24]. As longer fibers were incorporated, the slower the flow and the higher the E 00 .…”

Electrically conducting polypropylene/polyaniline‐grafted‐short glass fiber composites: Microstructure and dynamic mechanical analysis

“…Adding glass fibers to PP is relatively easy and very effective for reinforcing tensile, flexural, and impact properties [6–8]. Several investigators have studied experimental [6–11] and theoretical models [12–14] on glass fiber‐reinforced PP.…”

Caracterização Mecânica de Compósitos de Poliamida/Fibra de Carbono Via Ensaios de Cisalhamento Interlaminar e de Mecânica da Fratura

“…Um grande número de variáveis pode estar correlacionado a esse processo, tais como: características do polímero e do reforço, temperatura, pressão e tempo de moldagem, geometria do molde, entre outras. Além disso, é bem conhecido que para qualquer material com comportamento viscoelástico, as características reológicas afetam as propriedades finais do compósito obtido [11][12][13] . A viscosidade do polímero e a permeabilidade do reforço são, também, dois parâmetros importantes neste processo.…”

“…O conteúdo volumétrico de fibras no compósito tem um importante impacto nas propriedades mecânicas do material. Entretanto, o aumento no conteúdo de fibras pode resultar em uma maior resistência à infiltração da matriz no reforço durante o processamento, podendo gerar descontinuidades no compósito final [11][12][13][14][15] .…”