The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers.
The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers.
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DOI：
10.1016/j.radphyschem.2012.10.007
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发表时间：
2013-02
期刊：
影响因子：
--
通讯作者：
Maitland DJ
中科院分区：
文献类型：
--
作者：
Hearon K;Smith SE;Maher CA;Wilson TS;Maitland DJ
研究了自由基阻滞剂对新型辐射交联型聚氨酯形状记忆聚合物(SMPS)与丙烯酸酯辐射敏化剂共混体系的电子束交联性和热加工稳定性的影响。这项研究中的SMPS具有新的加工能力--即能够像热塑性塑料一样被熔融加工成复杂的几何形状，并使用电子束照射在第二步进行交联。为了提高辐射交联敏感性，将辐射增敏剂季戊四醇三丙烯酸酯(PETA)与由2-丁烯-1，4-二醇和三甲基六亚甲基二异氰酸酯(TMHDI)制成的热塑性聚氨酯SMPS溶液共混。由于热塑性塑料熔体加工方法，如注射成型，通常在较高的温度下进行，因此增感剂的热不稳定性是一个主要的加工问题。可以添加自由基抑制剂来提供热稳定；然而，抑制剂也会不希望地抑制辐射交联。在本研究中，我们量化了缓蚀剂1，4-苯二酚(BQ)对PU/PETA共混体系的热稳定和辐射交联抑制作用。对辐照样品的Sol/Gel分析表明，在0-10000ppm的浓度范围内，缓蚀剂对凝胶分数的影响很小，动态力学分析表明BQ组成与橡胶弹性模量之间只有轻微的负相关。1，4-苯二酚对丙烯酸类增感剂的热稳定效果也很好。如果用10,000 ppm BQ稳定，聚合物共混物可以加热到150°C长达5小时，或加热到125°C长达24小时，如果用1000 ppm BQ稳定，也可以加热到125°C长达5小时，而不发生增感反应。我们相信，这项研究为操纵辐射交联剂和辐射增敏剂的热稳定相互竞争的机理的方法提供了重要的见解，从而促进了辐射交联型热塑性SMPS的进一步开发。
The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities—that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0-10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150°C for up to five hours or to 125°C for up to 24 hours if stabilized with 10,000 ppm BQ and could also be heated to 125°C for up to 5 hours if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of radiation sensitizers, thereby facilitating further development of radiation crosslinkable thermoplastic SMPs.
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影响因子：
4.1
作者：
Di Prima, M. A.;Lesniewski, M.;Campbell, D.
通讯作者：
Campbell, D.
影响因子：
3.5
作者：
BATCH, GL;MACOSKO, CW
通讯作者：
MACOSKO, CW
影响因子：
3
作者：
Fabrizio, Quadrini;Loredana, Santo;Anna, Squeo Erica
通讯作者：
Anna, Squeo Erica
影响因子：
--
作者：
Small W 4th;Singhal P;Wilson TS;Maitland DJ
通讯作者：
Maitland DJ
DOI：
10.1016/j.nimb.2005.09.013
发表时间：
2006-02-01
影响因子：
1.3
作者：
Frounchi, M;Dadbin, S;Panahinia, F
通讯作者：
Panahinia, F