# EFFECTS OF MOULDING CONDITION AND CURING ATMOSPHERE ON THE FLEXURAL PROPERTIES OF VINYL ESTER

> Title: EFFECTS OF MOULDING CONDITION AND CURING ATMOSPHERE ON THE FLEXURAL PROPERTIES OF VINYL ESTER Page Range: p.61-64 Author(s): Nouranian S; Lee J; Torres G W; Lacy T E; Toghiani H; Pittman Jr C U File size: Download the pdf (subscribers only)...

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Published: 2013-02-01T00:00:00+00:00
Categories: Polymers and Polymer Composites

**Title: EFFECTS OF MOULDING CONDITION AND CURING ATMOSPHERE ON THE FLEXURAL PROPERTIES OF VINYL ESTER**
 Page Range: p.61-64
 Author(s): Nouranian S; Lee J; Torres G W; Lacy T E; Toghiani H; Pittman Jr C U
 File size:
 ![](http://dload.gif) [Download the pdf](http://journals.asp?Page=111&JournalDownload=ON&JournalType=ppc&JournalIssue=ppc21-2&JournalID=101825&JIP=) (subscribers only)
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 Journal: Polymers and Polymer Composites
 Issue Year: ppc
 Volume: 21
 Issue No: No.2

**Abstract**
 The effects of moulding condition and curing atmosphere on the flexural properties of a neat 33 wt.%-styrene epoxy vinyl ester (VE) were investigated. Specimens were prepared using either open or closed moulds, and thermally cured under either air or nitrogen atmosphere. Four-point bending tests were performed with both the top ('air-side') and the bottom ('mould-side') surfaces of the cured specimens in tension. The mean flexural moduli for nitrogen-cured and closed-mould specimens were 3% and 9% higher than for air-cured specimens, respectively. However, the mean flexural strength for open-mould air-cured specimens with their air-sides loaded in tension were 65% lower than the mean flexural strengths of open-mould nitrogen-cured or closed-mould specimens. This likely resulted from partial VE resin curing inhibition due to oxygen diffusion into the free surface region of the open-mould air-cured specimens. This creates gradients in the local stiffness and strength in the near-surface region due to lower crosslink density. This effect may be particularly important for thin specimens. These results underscore the significance of exposure to air during open-mould curing on the cured VE flexural properties. Such assessments are crucial for composite part manufacturing utilizing VEs. 26 Refs.

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