Effects of additives on the cure kinetics of vinyl ester pultrusion resins

Abstract

Pultrusion is a highly efficient composite manufacturing process. To accurately describe pultrusion, an appropriate model of resin cure kinetics is required. In this study, we investigated cure kinetics modeling of a vinyl ester pultrusion resin (Atlac 430) in the presence of aluminum hydroxide (Al(OH)3) and zinc stearate (Zn(C18H35O2)2) as processing additives. Herein, four different resin compositions were studied: neat resin composition, composition with Al(OH)3, composition comprising Zn(C18H35O2)2, and composition containing both Al(OH)3 and Zn(C18H35O2)2. To analyze each composition, we performed differential scanning calorimetry at the heating rates of 5, 7.5, and 10 K/min. To characterize the cure kinetics of Atlac 430, 16 kinetic models were tested, and their performances were compared. The model based on the [Formula: see text]th-order autocatalytic reaction demonstrated the best results, with a 4.5% mean squared error (MSE) between the experimental and predicted data. This study proposes a method to reduce the MSE resulting from the simultaneous melting of Zn(C18H35O2)2. We were able to reduce the MSE by approximately 34%. Numerical simulations conducted at different temperatures and pulling speeds demonstrated a significant influence of resin composition on the pultrusion of a flat laminate profile. Simulation results obtained for the 600 mm long die block at different die temperatures (115, 120, 125, and 130 °C) showed that for a resin with a final degree of cure exceeding 95% at the die exit, the maximum difference between the predicted values of pulling speed for a specified set of compositions may exceed 1.7 times.

Effects of the Pre-Consolidated Materials Manufacturing Method on the Mechanical Properties of Pultruded Thermoplastic Composites

“…Moreover, the effects of technological regimes of PCT manufacturing and thermoplastic pultrusion on mechanical properties, occurrence of manufacturing-induced shape distortions, porosity, and morphology of corresponding composites will be studied as well. In particular, the authors plan to investigate the influence of pulling speed [ 39 , 40 ], temperature regime, presence of additives [ 41 ], and carbon nanotubes [ 42 ]. The obtained experimental results will be used for the further multicriteria optimization of pultrusion manufacturing conditions [ 43 , 44 ].…”

Cost-efficient, automated, and sustainable composite profile manufacture: A review of the state of the art, innovations, and future of pultrusion technologies

“…Over the last 50 years, more than 1400 papers have been published in scientific journals and conference proceedings about pultrusion 3 , which includes theoretical and experimental studies of various thermoset resin systems [30][31][32][33][34][35][36][37][38][39][40], thermoplastics [20,22,24,[41][42][43][44][45][46][47][48][49], as well as alternative and renewable materials and reinforcements [50][51][52][53][54]. For resin-injection pultrusion, in particular, where analyses of the impregnation flow is essential to ensure saturation [15,[38][39][40]55,56], studies have considered geometrical configurations of the injection chamber [57][58][59][60][61] as well as other process parameters such as the profile-advancing pulling speed [62], resin viscosity [63], and fibre permeability [64].…”

Fiber-Reinforced Polymers in Freeform Structures: A Review

“…Typical FRP composites consist of a polymer matrix with reinforcing fibers. Polymers are divided into three groups according to the chemical structure: thermoplastics (or thermosoftening plastics) [27], elastomers, and thermosets (or thermosetting plastics) [28,29]. All these types of polymers can be used as a matrix in fiberreinforced composites.…”