Interactions in Miscible Blends of Poly(styrene-co-methacrylic acid) with Copolymers Containing Vinylpyrrolidone and Vinylpyridine Groups
Interactions in Miscible Blends of Poly(styrene-co-methacrylic acid) with Copolymers Containing Vinylpyrrolidone and Vinylpyridine Groups
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DOI：
10.1021/ma011142w
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发表时间：
2001-10
期刊：
影响因子：
5.5
通讯作者：
Heidi R. Motzer;P. Painter;M. Coleman
中科院分区：
文献类型：
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作者：
Heidi R. Motzer;P. Painter;M. Coleman
本文报道了含互补功能基乙烯基吡咯烷酮(VPR)和2-乙烯基吡啶(VPy)的苯乙烯-甲基丙烯酸(STMAA)共聚物共混物的红外光谱研究结果。MAA/VPy相互作用的性质以前已经被其他几个研究小组研究过，他们都同意MAA和VPy基团之间的相互关联很强。1-4然而，这种相互作用是否应该被归类为离子(络合物)性质或强氢键，一直是一些争论的主题。周等人。比较了聚丙烯酸(PAA)、聚乙烯吡啶(PVPy)与聚甲基丙烯酸(PMAA)、聚乙烯吡啶(PVPy)的络合物。1本质上，这些研究人员使用FTIR和X射线光电子能谱(XPS)相结合的方法来研究相互作用的性质。结果表明，在PMAA和PVPy共混物中，MAA和VPy基团之间的相互作用以氢键为主，而在类似的PAA共混物中，离子相互作用占主导地位。他们将此归因于PAA的酸度高于PMAA。2这里介绍的工作涉及含有MAA的共聚物与含有VPR或VPy链段的共聚物的混合。MAA和VPR(或VPy)链段通过与“惰性”苯乙烯链段的共聚基本上被“稀释”。这种混合物在普通溶剂中不会从溶液中析出，因此形成可混溶的混合物是可行的。本实验室合成了苯乙烯-乙烯基吡咯烷酮(STVPr)、苯乙烯-2-乙烯基吡啶(STVPy)和苯乙烯-甲基丙烯酸(STMAA)共聚物，详细内容分别载于Motzer，5 Zhang，6和Cveland，7的论文中。在室温下，从1%(w/v)的四氢呋喃溶液中，在KBrR窗口上浇铸薄膜，制备了这些共聚物的共混物。在室温下风干后，将窗户放在60摄氏度的真空烤箱中过夜，以完全去除溶剂。所有薄膜都足够薄，在符合比尔-兰伯特定律的吸光度范围内。红外光谱记录在Digilab FTS-45型傅里叶变换红外光谱仪上，分辨率为2 cm-1。热分析在精工DSC-U220型差示扫描量热仪上进行。升温速率为20℃min-1，计算玻璃化转变温度作为热容变化的中点。我们将首先检查STMAA{9}(一种苯乙烯-甲基丙烯酸共聚物)的混合物
In this paper we report the results of infrared spectroscopic studies of styrene-co-methacrylic acid (STMAA) copolymer blends with styrene copolymers containing the complementary functional groups vinylpyrrolidone (VPr) and 2-vinylpyridine (VPy). The nature of the MAA/VPy interaction has been previously studied by several other research groups who were all in agreement that the interassociation between MAA and VPy groups is strong. 1-4 However, whether or not the interaction should be classified as ionic (complex) in nature or a strong hydrogen bond has been a subject of some debate. Zhou et al. compared complexes of poly-(acrylic acid)(PAA) and poly (vinylpyridine)(PVPy) with those of poly (methacylic acid)(PMAA) and PVPy. 1 In essence, these researchers used a combination of FTIR and X-ray photoelectron spectroscopy (XPS) to study the nature of the interaction. Their results showed that hydrogen bonding is the principal interaction involving MAA and VPy groups in PMAA blends with PVPy, while in analogous PAA blends ionic interactions dominated. This they attributed to the higher acidity of PAA visa-vis PMAA. 2The work presented here involves the mixing of copolymers containing MAA with those containing VPr or VPy segments. The MAA and VPr (or VPy) segments are substantially “diluted” by copolymerization with “inert” styrene segments. Such mixtures do not precipitate from solution in a common solvent, and the formation of miscible blends is feasible. The styrene-co-vinylpyrrolidone (STVPr), styrene-co-2-vinylpyridine (STVPy), and styrene-co-methacrylic acid (STMAA) copolymers used in this study were synthesized in our laboratories, and details are contained in the theses of Motzer, 5 Zhang, 6 and Cleveland, 7 respectively. Blends of these copolymers were prepared by casting films onto KBr windows at room temperature from a 1%(w/v) solution in THF. Following air-drying at room temperature, the windows were placed in a vacuum oven overnight at 60 C to completely remove the solvent. All films were thin enough to be within an absorbance range where the Beer-Lambert law is obeyed. Infrared spectra were recorded on a Digilab model FTS-45 Fourier transform infrared (FTIR) spectrometer at a resolution of 2 cm-1. Thermal analysis was performed on a Seiko DSC-U220 differential scanning calorimeter. A heating rate of 20 C min-1 was used, and glass transition temperatures were calculated as the midpoint of the heat capacity change. We will commence with an examination of blends of STMAA {9}(a styrene-co-methacrylic acid copolymer