Influence of post curing on GFRP hybrid composite

Chavan, Vithal Rao; Dinesh, K.; Veeresh, K; Algur, Veerabhadrappa; Shettar, Manjunath

doi:10.1051/matecconf/201814402011

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…Sufficient mobility was provided at 60 °C and the limit to crosslink formation and intermolecular forces appeared to be reached. Beyond this point, mechanical properties declined, suggesting a breakdown of intermolecular forces and bonds [ 58 ]. The increased crosslinking density of F6 appeared to have brought brittleness to the structure ( Figure 7 ), as results showed a more drastic decline in UTS from 60 °C + UV for 30–40 min.…”

Section: Resultsmentioning

confidence: 99%

3D Printing Soft Magnet: Binder Study for Vat Photopolymerization of Ferrosilicon Magnetic Composites

Okoruwa,

Sameni,

Borisov

et al. 2023

Polymers

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Liquid Crystal Display (LCD) masking is a 3D printing technique that can produce soft magnetic composite parts to high resolution and complexity for robotics and energy electronics applications. This additive manufacturing technique has the potential to produce larger, lighter-weight, more efficient, and more durable parts for automotive and mechanical applications. This study conducted a binder study to create a low-viscosity and stiff binder capable of loading at least 60 v/v% Fe-6.5 wt%Si particles. Percolation Theory was applied to anticipate the magnetic interaction of suspended particles. A series of binders were formulated, with adjustments to diluent ratios. The behavior of the binders was assessed by studying their rheological properties, conversion rates, and mechanical properties. A post-cure study was conducted across various energy settings using UV, thermal, and a combination of both energy sources to find the combination that provided the best mechanical properties. As a result, 64 v/v% Fe-6.5 wt%Si loading was achieved and cured using UV light of 405 nm wavelength. Vibrating Sample Spectroscopy (VSM) was used to characterize the composite’s magnetic behavior, and a significant increase in saturation magnetization and negligible change in coercivity was observed when the added load exceeded the percolation threshold.

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Section: Resultsmentioning

confidence: 99%

3D Printing Soft Magnet: Binder Study for Vat Photopolymerization of Ferrosilicon Magnetic Composites

Okoruwa,

Sameni,

Borisov

et al. 2023

Polymers

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“…In both situations, adverse effects on the matrix resin, which crystallizes with increasing temperature, have been reported. 3…”

Section: Literature Reviewmentioning

confidence: 99%

“…In both situations, adverse effects on the matrix resin, which crystallizes with increasing temperature, have been reported. 3 The literature on post curing mainly presents results related to the treatment of composite parts subjected to a single cycle of post curing in order to improve their properties. Although this claim is conventionally accepted, the results of this investigation showed some limitations in improving properties with evidence of adverse effects due to multiple cycles of post curing.…”

Section: Literature Reviewmentioning

confidence: 99%

“…In these different studies, high temperature curing as well as post curing were beneficial to improve the properties with optimal values achieved. [2][3][4][5][6][7][8][9][10][11][12][13][14] This is the case with Na et al (2018), who investigated the effects of temperature on the mechanical properties of adhesively bonded basalt fibre reinforced polymer and aluminium joints. Their results showed that the mechanical properties change significantly, when the temperature approaches or exceeds the Tg.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Articles published in references [2][3][4][5][6][7][8][9][10][11][12][13][14] demonstrate that exposing composite parts to high temperatures or applying a single post cure cycle affects their thermal, physical and mechanical properties. However, the literature barely addresses the effects of multiple post cure cycles, such as those encountered in thermosetting composite repairs or composite aging phenomena due to exposure to high temperature.…”

Section: Literature Reviewmentioning

confidence: 99%

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Effects of multiple post cure cycles on properties of composite carbon fibre and epoxy materials

Sambayi

Heyns

2023

Journal of Composite Materials

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Post-curing cycles have an effective impact on the thermal and mechanical properties of thermoset composite materials. Typically, post-cure cycles use heat to expose cured resin parts to high temperatures in an attempt to maximize their final properties. In most cases, these processes allow composite parts to achieve the highest possible strength and become stable. In industrial practice, however, it has been found that there are potential consequences of performing localized repairs on composite parts in an autoclave where the localized repair undergoes a normal curing process while the parent part undergoes an additional curing process. Thus, for the parent part, prolonged exposure to high temperatures can trigger a process of decomposition of the resin matrix, as could be the aging phenomena of composites in service. In such a scenario, two practical questions are worth asking: (1) to what extent can a resin matrix be post cured without risking degrading its thermal properties? (2) what are the residual mechanical and physical properties resulting from prolonged exposure of composite parts to elevated temperatures? In this work, an analysis was carried out to estimate the potential adverse effects on thermoset composite parts made of carbon fibre and epoxy resin materials commonly used in aerospace, in terms of thermal, physical and mechanical properties after a long exposure to high temperatures caused by multiple post cure cycles. Two types of prepreg laminates were used to make monolithic test panels using twill and plain weave architectures for the M21 and 8552 test panels respectively. Thermal tests were conducted to evaluate the evolution of the degree of cure, the glass transition temperature and the inter-laminar shear strength of post-cured panels, which were subjected to a different number of post cure cycles. The study found that multiple post cure cycles alter thermal properties, which in turn have adverse effects on physical and mechanical properties. The results demonstrated that the two types of composite materials respond differently to changes in properties. Twill weave panels quickly reach full cure after three stages while plain weave panels have undergone gradual curing. This difference in the curing process of the resin matrix clearly influenced the changes in the measurements of shear, surface hardness and compressive strengths.

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