Physical and mechanical properties of pultruded composites containing fillers and low profile additives

Abstract

This article deals with the effect of fillers and additives content on the physical and mechanical properties of unidirectional pultruded glass/polyester composites. The physical characterization consisted of determining the void volume fraction (Vv), density, shrinkage ratio, coefficient of thermal expansion (CTE), and dynamic mechanical properties. The mechanical tests consisted of three-point-bending tests under static, impact, and fatigue loading. The low profile additive (LPA) has been found to compensate the cure shrinkage by microvoid formation. Dynamic mechanical analysis measurements show that the LPA slightly lowers the glass transition temperature Tg and increases the internal damping Tan ␦. The transverse coefficient of thermal expansion was found to be sensitive to the LPA content. Three-point bending tests show that the interlaminar shear strength (ILSS) is slightly sensitive to the fillers and LPA content, but the flexural strength is not affected. Impact test results on short beam shear and flexural specimens show the same behavior as in the static tests except that the LPA content has a detrimental effect on the flexural impact properties. The fatigue tests performed show that the effect of fillers is not significant, while the LPA effect is mixed. It seems that there is an LPA content for which the fatigue resistance is maximized. Finally, the wide range of behaviors and span-to-depth ratios investigated suggest that the ILSS as measured according to the ASTM 2344 recommendations can be largely misleading because of the unavoidable compressive yielding under the loading nose. For the materials investigated, higher span-to-depth ratio are more representative of the ILSS. POLYM. COMPOS., 27:71-81, 2006.

Relation between volumetric changes of unsaturated polyester resin and surface finish quality of fiberglass/unsaturated polyester composite panels

“…Also, the CTE increases first with the LPA content up to 5% and decreases afterward between 5% and 40%. This behavior is in agreement with CTE measurements performed in [34]. This reduction of thermal expansion was attributed to the presence of microvoids in the microstructure due to the LPA shrinkage compensation mechanism.…”

“…It was determined that there is an optimal LPA content to compensate for cure shrinkage that varies depending on the resin and LPA systems studied. Boukhili et al [34] also examined the influence of LPA on the thermal expansion. It was observed that the coefficient of thermal expansion (CTE) of a glass/polyester composite increased with an LPA content variation from 0% to 15%, but then decreased afterward at 20% LPA content.…”

Effect of low-profile additives on thermo-mechanical properties of glass fiber-reinforced unsaturated polyester composites

“…A similar trend was found in the literature for the Young's modulus variation with LPA content [10][11][12][13][14][15] and the flexural strength evolution with an increase in LPA content for pultruded composites. 17 In the case of the 40% LPA content, the flexural modulus and strength standard deviations appeared to be higher. This was attributed to a less homogeneous structure of the matrix due to the development of the LPA rich phase.…”

“…17 With the addition of LPA, the apparent short-beam strength decreases. Reductions of 18% and 21% of the apparent short-beam strength were obtained at 10% and 40% LPA contents, respectively.…”

Polymer Composite Manufacturing Using a Pultrusion Process: A Review

“…Generally, additive and fillers are used in the pultrusion process to enhance the physical and mechanical properties of the pultruded profiles, to solve production difficulty and to reduce the production cost (Boukhili et al, 2006). sulfonic acid (Ma et al,1997) Science Publications Figure 9 shows typical load-displacement curves for pultruded glass/polyester composites containing different amounts of fillers and tested at L/h = 24.…”