不对称嵌段共聚物增容对共混物相形貌调控及机理研究

发布时间：2018-05-15 07:28

本文选题：不对称两嵌段共聚物 + 增容　；参考：《宁波大学》2017年硕士论文

【摘要】：本论文主要探究了不对称两嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸甲酯(PS-b-PMMA)增容聚甲基丙烯酸环己酯/聚甲基丙烯酸甲酯(PCHMA/PMMA)二元不相容共混体系的相形貌调控机理。通过本研究,深入探究了加工过程中共混顺序,均聚物分子量,不对称两嵌段共聚物嵌段比,共混体系粘度,加工过程中胶束的迁移扩散行为以及不对称两嵌段共聚物增容动力学与热力学之间的关系,研究这些因素之间的内在规律对于共混物相形貌的调控及力学性能的影响,用自洽场理论模型计算和“干-湿”刷理论进行解释和验证不对称嵌段共聚物增容对于共混物相形貌调控的实质机理。本文所进行的研究工作如下:1、论文第2章,以聚甲基丙烯酸环己酯/聚甲基丙烯酸甲酯(PCHMA/PMMA)的不相容共混体系为研究对象,研究了加工过程中共混顺序对不对称两嵌段共聚物PS-b-PMMA增容PCHMA/PMMA共混体系界面与胶束的竞争关系,从而探究出共混顺序对于不相容共混物相形貌的影响。研究表明,在最优共混步骤下加入不对称两嵌段共聚物SM1(NPS/NPMMA=1:9)和SM2(NPS/NPMMA=9:1),并减小共混物体系中均聚物PMMA分子量可以显著改善共混物中的相形态和相尺寸,促使不对称嵌段共聚物在两相界面,提高了增容效率。这跟分散相体系粘度和共混时所形成的胶束热力学状态的稳定性有关。增加PMMA分子量会改变不对称嵌段共聚物在两相界面之间的曲率,从而造成在界面的嵌段共聚物不稳定,又会扩散至PMMA相内部形成胶束,从而形成不同的分散相胶束化相形貌。2、在明确了共混顺序对于不对称两嵌段共聚物PS-b-PMMA增容PCHMA/PMMA共混体系相形貌的影响之后,在论文的第3章,研究了不对称两嵌段共聚物嵌段比和均聚物分子量对于共混物相形貌的调控机理。研究发现,较为对称嵌段比例结构的不对称两嵌段共聚物SM4(NPS/NPMMA=6:4)增容效果好,相尺寸小,在分散相PMMA分子量低的情况下嵌段共聚物基本都在界面上。不对称两嵌段共聚物SM1和SM2由于链段结构和比例的影响更容易在体相形成胶束,SM3(NPS/NPMMA=8:2)介于两者之间。自洽场理论模型的计算也很好解释了这个现象。并且通过调控均聚物分子量改变内外围的乳化效果,改变链段之间的溶胀程度可以影响嵌段共聚物在界面的利用率,同时也影响着不对称嵌段共聚物在界面的稳定性,对于共混物相形貌的调控具有深刻的意义。不仅如此,研究还发现拥有胶束的共混物相形貌也同时反映出共混物性能的变化。不对称两嵌段共聚物增容,尤其是两者1:9和9:1嵌段比的SM1和SM2嵌段共聚物非但没能增强材料的拉伸性能,反而由于胶束的存在降低了共混体系的拉伸强度。3、为证实不对称两嵌段共聚物PS-b-PMMA在PCHMA/PMMA共混体系中所形成胶束的扩散迁移以及界面嵌段共聚物的热力学稳定性对于共混体系相形貌的影响。在论文的第4章,我们研究了不对称两嵌段共聚物PS-b-PMMA的胶束迁移扩散行为以及增容PCHMA/PMMA共混体系动力学与热力学的关系。研究发现,胶束的热力学稳定性因素也是影响胶束扩散的一个至关因素,嵌段越长,与该嵌段相容的相与其形成的“湿刷”程度越大,此时链段相互作用力越大,链段相互摩擦力越强,嵌段的链段运动困难,分子量大的嵌段共聚物在体相的扩散速率慢,而分子量小的嵌段共聚物在体相扩散速率快。研究还发现不对称两嵌段共聚物对不相容共混体系增容动力学与热力学因素都存在着影响,并且受不对称两嵌段共聚物嵌段比和共混体系分子量的影响。在分散相低分子量的情况下,不对称两嵌段共聚物SM1,SM2和SM3增容的PCHMA/PMMA不相容共混体系的动力学势垒较高,热力学因素起主要影响作用,较为对称的SM4增容的情况下动力学与热力学势垒相差不大,热力学影响因素并不明显;而在分散相高分子量的情况下,SM1,SM2,SM3和SM4增容的PCHMA/PMMA不相容共混体系的热力学势垒较低,依旧起主要影响作用,此时加工过程中动力学因素对不对称两嵌段共聚物增容PCHMA/PMMA不相容共混体系的影响并不是很大。
[Abstract]:In this paper, the mechanism of phase morphology regulation of asymmetric two block copolymer polystyrene -b- polymethyl methacrylate (PS-b-PMMA) Compatibilization of two element incompatible blends of poly (cyclohexyl methacrylate) / polymethyl methacrylate (PCHMA/PMMA) was investigated. The mass ratio of the asymmetric two block copolymer, the viscosity of the blend system, the migration and diffusion behavior of the micelles in the process and the relationship between the compatibilization kinetics and the thermodynamics of the asymmetric two block copolymers, and the influence of the inherent laws between these factors on the control and mechanical properties of the blend phase shape and the mechanical properties of the blends, using the self consistent field theory model Calculation and "dry wet" brush theory are used to explain and verify the essential mechanism of asymmetric block copolymer compatibilization. The research work in this paper is as follows: 1, the second chapter of this paper is the research object of the incompatible blend system of cyclohexyl methacrylate / polymethyl methacrylate (PCHMA/PMMA). In the process, the competition relationship between the PCHMA/PMMA blend interface and the micelle of the asymmetric two block copolymer PS-b-PMMA was added to explore the influence of the blending order on the phase appearance of the incompatible blends. The study showed that the asymmetric two block copolymer SM1 (NPS/NPMMA=1:9) and SM2 (NPS/NPMMA) were added under the optimal blending procedure. =9:1), and reducing the PMMA molecular weight of the homopolymer in the blends can significantly improve the phase state and phase size in the blends, prompting the asymmetric block copolymers to increase the compatibilization efficiency at the two-phase interface. This is related to the stability of the micelle thermodynamic state formed when the viscosity of the dispersed phase system and the blend formed. The increase of the molecular weight of the PMMA will change. The curvature of the asymmetric block copolymer at the two phase interface leads to the instability of the block copolymer at the interface and the diffusion of the micelles into the PMMA phase, thus forming a different dispersed phase micellization phase appearance.2. In the clear blending order, the phase appearance of the asymmetric two block copolymer PS-b-PMMA Compatibilization of the PCHMA/PMMA blends In the third chapter of the paper, the regulation mechanism of the asymmetric two block block ratio and the molecular weight of homopolymer on the phase morphology of the blends is studied. It is found that the asymmetric two block copolymer SM4 (NPS/NPMMA=6:4) has good compatibilization effect, small phase size and low molecular weight of PMMA in dispersed phase. The lower block copolymers are basically at the interface. Asymmetric two block copolymers SM1 and SM2 are more likely to form micelles in bulk due to the influence of the chain structure and proportion. The SM3 (NPS/NPMMA=8:2) is between the two. The calculation of the self consistent field theoretical model also explains this phenomenon well. And the internal and external milk is changed by regulating the molecular weight of the homopolymer. The effect and the degree of swelling between the segments can affect the utilization of the block copolymer at the interface, and also affect the stability of the asymmetric block copolymer at the interface. It is of great significance to the control of the phase appearance of the blends. The changes in performance. The compatibilization of asymmetric two block copolymers, especially the SM1 and SM2 block copolymers of both 1:9 And 9:1 block ratios, does not enhance the tensile properties of the materials, but reduces the tensile strength.3 of the blends due to the presence of micelles, which proves that the asymmetric two block copolymers are formed in the PCHMA/PMMA blends. The influence of the diffusion and migration of micelles and the thermodynamic stability of the interface block copolymers on the phase morphology of the blends. In the fourth chapter of the paper, we studied the micellar migration and diffusion behavior of the asymmetric two block copolymer PS-b-PMMA and the relationship between the kinetics of the compatibilization of the PCHMA/PMMA blends and the thermal mechanics. The stability factor is also a crucial factor affecting the diffusion of micelles. The longer the block is, the greater the degree of "wet brush" which is compatible with the block, the greater the interaction force of the chain segment, the stronger the interaction force of the chain segment, the difficulty of the segment chain movement and the slow diffusion rate of the block copolymer with large molecular weight in the body phase, and the molecule of the molecule. It is also found that asymmetric two block copolymers have an influence on the compatibilization kinetics and thermodynamic factors of incompatible blends, and are influenced by the ratio of the asymmetrical two block copolymers and the molecular weight of the blends. Under the condition of the low molecular weight of the dispersed phase, asymmetric two inlay. The dynamic potential barrier of the SM1, SM2 and SM3 Compatibilization of the PCHMA/PMMA incompatible blend system is higher, and the thermodynamic factors play a major role. In the case of the more symmetrical SM4 compatibilization, there is little difference between the kinetics and the thermodynamic barrier, and the thermodynamic factors are not obvious. In the case of the dispersed phase high molecular weight, SM1, SM2, SM3 and SM4 increase. The PCHMA/PMMA incompatible blend system has a lower thermodynamic barrier and still plays a major role. In this process, the influence of dynamic factors on the compatibilization of asymmetric two block copolymer on PCHMA/PMMA incompatible blends is not very significant.

【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631

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