CAS OpenIR  > 中科院上海应用物理研究所2004-2010年
辐射改性SBS及其与PA6共混体系性能的研究
Alternative TitleStudies on γ-ray irradiated SBS and its application in Polyamide 6/SBS Blends
张艳
Subtype博士
Thesis Advisor盛康龙
2008-05-26
Degree Grantor中国科学院上海应用物理研究所
Place of Conferral上海应用物理研究所
Keyword尼龙6 Sbs 聚合物合金 相容性 辐射接枝 辐射交联
Abstract本论文就聚合物共混改性和苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)在改性尼龙6(PA6)中的应用进行了充分的文献调研。为解决PA6与SBS的相容性问题,提高PA6/SBS聚合物合金的性能,我们利用SBS的辐射接枝与辐射交联对其进行辐射改性。辐射接枝可反应的极性官能团于SBS长链上,通过接枝单体与PA6的化学反应改善PA6与SBS的相容性;辐射交联在PA6/SBS内形成三维网络结构,使两相间产生特殊的强制互容作用,赋予聚合物合金更好的性能。通过一系列的实验详细研究了辐射改性SBS提高PA6/SBS共混物相容性的机理。辐射改性增容后PA6/SBS聚合物合金的性能明显提高。具体的研究结果概述如下: 1. SBS辐射接枝共聚 利用60Co γ射线通过不同的接枝方法将不同的单体接枝到SBS长链上,采用双单体接枝法可以有效的提高单体的接枝率。运用基团贡献法计算可知SBS接枝极性单体后接枝共聚物溶解度参数随之增加,特别是其中极化分量和氢键分量增加明显。 2. 辐射接枝增容PA6/SBS机理及性能 熔融共混PA6与SBS,选取三种SBS接枝物作为相容剂能有效增容PA6/SBS共混物,增容效果依次为SBS-g-MAH>SBS-g-MAA>SBS-g-DBM。增容后的共混物合金中,SBS分散相分布均匀,粒径减小;增容后PA6/SBS合金的粘度,弹性模量均增大,两相的玻璃化温度接近,抗冲击性能提高,吸水率降低。SBS可以有效的增韧PA6,增韧机理可以归结为银纹-剪切带增韧机理。 3. SBS辐射交联效应 γ射线下SBS主要发生交联反应。在流变性能上表现为随着吸收剂量的增大,SBS粘度与弹性模量均增加。辐照交联后SBS仍保持两相结构,拉伸强度增大,断裂伸长率降低,抗穿刺性提高,PB嵌段的玻璃化温度提高。辐照温度对SBS的交联有显著影响:相对常温辐照,高温辐照时SBS的交联效率提高,起始凝胶剂量降低,SBS的交联符合Charlesby-Pinner关系式,SBS构型和嵌段比对交联没有影响。高温辐照时PS嵌段发生裂解反应。无论是常温辐照还是高温辐照,线型SBS的辐射G值大于星型SBS;辐照温度对线型SBS的G值基本没有影响,但是对星型的G值有较大影响。 4. 辐射交联增容PA6/SBS机理及性能 PA6/SBS共混物经过γ射线辐照后,SBS相发生交联。辐射交联后PA6/SBS合金的粘度和弹性模量增大,机械性能有所提高。辐射交联后PA6/SBS合金两相的玻璃化温度并未接近,说明相容性的提高是由于SBS的交联在共混物中形成三维网络结构,使两相间产生特殊的强制互容作用。
Other AbstractIn this thesis, an extensive literature survey on polymer alloy is carried out, and technical developments to improve properties of styrene-butadiene-styrene triblock copolymer (SBS) for its applications in polyamide 6/SBS blends are reviewed. In an attempt to give a better solution to the problems related to undesirable compatibility of SBS with polyamide 6, we propose a new method to modify the SBS molecular chains through radiation graft copolymerization and radiation crosslinking. Grafting a monomer with polar functional groups onto the SBS molecules improves compatibility of SBS with polyamide 6 by the chemical interactions between the monomer and the amine groups of polyamide 6. Crosslinking of SBS molecular chains improves compatibility of polyamide 6/SBS blends by the three-dimensional network structure. Mechanisms of the radiation effects were studied with a series of SBS samples irradiated by 60Co γ-rays. The results can be summarized as follows. 1. Radiation grafting copolymerization of SBS Different polar monomers were grafted onto SBS by 60Co γ-rays. Radiation grafting of binary monomers could increase the grafting yield. The increased solubility parameters of the grafted SBS copolymer, especially the contributions by the polarization part and the hydrogen-bond, were obtained by the method of group contribution calculation. 2. Performance of polyamide 6 blended with radiation-grafting-functionalized SBS The compatibility improvement by grafting three copolymers, as the compatibilizer of polyamide 6/SBS blends, was ordered as follow: SBS-g-MAH>SBS-g-MAA>SBS-g-DBM. Polyamide 6 blended with grafted SBS had smaller-sized SBS disperse phase as well as increased storage modulus and impact resistance, and the glass transition temperature of polyamide 6 and SBS were close to each other. The toughening mechanism of polyamide 6/SBS blends was craze-shear band toughening. 3. Radiation crosslinking effect on SBS SBS molecular chains can be crosslinked under γ-ray irradiation. With rising radiation dose, the storage modulus G' and the viscosity increased. Additionally, the Tg of PB block of crosslinked SBS shifted to higher temperature. The tensile strength and the puncture resistance of SBS were enhanced with increasing absorbed dose. Behaviors of SBS irradiated at elevated temperature differ greatly from the irradiation performed at ambient temperature. Higher crosslinking efficiency was obtained at higher temperature though the dominance of chain scission of the PS block during the irradiation process. Under irradiation at elevated temperature, the crosslinking can be described by the Charlesby-Pinner equation, and the SBS configuration and block ratio did not affect crosslinking. 4. Performance of polyamide 6 blended with radiation crosslinked SBS SBS can be crosslinked in polyamide 6/SBS blends irradiated by γ-ray. The storage modulus G', the viscosity and the mechanical properties increased at high dose. The glass transition temperature of polyamide 6 and SBS were not close to each other after irradiation, indicating that the compatibility of blends was improved owing to "forced compatibility" produced by interpenetrating network.
Language中文
Document Type学位论文
Identifierhttp://ir.sinap.ac.cn/handle/331007/7260
Collection中科院上海应用物理研究所2004-2010年
Recommended Citation
GB/T 7714
张艳. 辐射改性SBS及其与PA6共混体系性能的研究[D]. 上海应用物理研究所. 中国科学院上海应用物理研究所,2008.
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