水性超支化聚氨脂的制备及性能研究

发布时间：2018-05-30 12:07

  本文选题：超支化聚氨酯 + 水溶性树脂　； 参考：《太原理工大学》2015年硕士论文

【摘要】：日益严峻的环境问题催生对新型节能环保材料的需求，生产节能、无害、安全系数高、易处理降解的材料成为当前热点。水性材料因使用水代替传统有机物做溶剂，具有成本低廉，环境友好，，不易燃烧等特点，受到市场的亲睐。水性聚氨酯结构具有良好的拉伸性能、挠抓性能、黏度控制、毒性低等优势，在高分子、新型功能材料领域被广泛研究和应用。传统的线性聚氨酯因缺少支链结构及交联度低，耐水性、耐热性、机械性能等方面劣于有机溶剂型聚氨酯。提高交联度是解决这一缺陷的有效途径，通过引入超支化结构，结合超支化三维球状结构黏度低、末端多官能团容易接枝改性（易于提高交联度）、溶解性好等优势，可大大提升水性聚氨酯的性能。 本文以超支化聚酯为核，通过核接枝法，合成了多种结构类似但基团比例不同的非离子水溶性超支化聚氨酯结构，进一步探讨影响其性质的结构因素并研究了其作为涂层用树脂的性能特征和原料配比。为超支化聚氨酯的固化成型应用以及新功能的开发提供技术支持。 本论文的主要过程如下： ①以二代超支化聚酯（HBPs）为核，通过异佛尔酮二异氰酸酯（IPDI）中的一个异氰酸根（─NCO）与HBPs末端羟基反应形成超支化聚氨酯结构，另一份─NCO接枝水性链段基团聚乙二醇单甲醚1000（MPEG-1000）及不饱和双键基团甲基丙烯酸羟乙酯（HEMA）。非离子亲水链段MPEG的引入使分子具有了水溶性，而双键则使其可实现自交联或与其他不饱和基团反应形成交联网状结构，合成的水性超支化聚氨酯（WHBPU）可作为水性聚合原料或是减水添加剂使用。使用(红外表征)FT-IR、（核磁分析）1H-NMR和（凝胶色谱）GPC对产物WHBPU的合成过程，结构特征，分子量大小进行了表征分析。 ②对产物的基础性质进行了研究测试，评价引入链段性质对最终结构的影响。通过紫外可见光谱分析(UV-vis)、激光粒度分析仪测试WHBPU的水溶性及分散体粒径；WHBPU的流变行为、结晶性由旋转流变仪、XRD等表征测得，显示分子间作用力对链段结构的影响进而造成表观性质的差异；热力学测试中示差扫描量热DSC和热重分析TG显示聚合物随着温度的升高，在形态、分子结构发生的变化，为评价其相结构以及耐热性提供依据。 ③UV-vis分析表明WHBPU水溶液在220nm处有最大吸光度，说明其末端不饱和基团可吸收紫外光固化成型。在4%Wt光引发剂Api-180作用下，利用紫外光将四种WHBPU固化为薄膜涂层，对其乳液稳定性、涂层硬度、平整性、吸水率、凝胶率、固化过程等研究，总结涂层性能与分子结构以及链段比例间的关系。 ④最后根据WHBPU结构具有俩亲性的特性，设计包覆染料亚甲基蓝小分子迁移到其不良溶剂氯仿相实验，利用UV-vis分析表征迁移亚甲基蓝水相中最大吸收峰的吸光度变化，算出迁移的小分子量，验证WHBPU的包覆迁移能力。 通过以上的实验设计、结构表征、性质分析得出： WHBPU合成过程由IPDI中-NCO与HBPs的末端-OH反应形成超支化聚氨酯结构，测试分子量趋势与设计相符但较理论值低，分子量分布良好。 WHBPU有良好的水溶性，溶解性随着亲水基团增加而增加，在水中形成不同的形态，造成粒径先增大后减小变化；结晶性与接枝的MPEG一致，为球晶结构，旋转剪切使晶体结构和分子间作用被破坏，造成黏度急剧下降，表现出非牛顿流体的特征；温度升高，聚合物熔融，硬软段的受热分解分别发生在310℃和370℃，呈俩段分解模式，耐热性能较优。 WHBPU作水性涂料树脂，乳液稳定性随着亲水基团含量增加而增强，漆膜综合性能与双键密度、交联度成正比；综合评价，WHBPU-4:8为涂层用最佳原料配比。 WHBPU可负载迁移亚甲基蓝分子进入氯仿相，最大可达到90%移除，负载量由亲疏段的比例决定。这一特性使其在涂膜染料保护、药物负载、水处理等领域有应用潜力和价值。
[Abstract]:The water - borne polyurethane has the advantages of low cost , environmental friendliness , low viscosity , low toxicity and the like , and has the advantages of low cost , environmental friendliness , difficult combustion and the like , and has the advantages of low cost , environmental friendliness , difficult combustion and the like , and is widely researched and applied in the fields of polymer and novel functional materials .

A variety of non - ionic water - soluble hyperbranched polyurethane structures with similar structure but different groups were synthesized by using hyperbranched polyester as the core . The structural factors affecting its properties were further discussed and the performance characteristics and raw material proportion of the resin were studied . The technical support was provided for the application of curing molding of hyperbranched polyurethanes and the development of new functions .

The main process of this paper is as follows :

The synthesis process , structural characteristics and molecular weight of the product WHBPU were characterized by FT - IR , 1H - NMR and ( gel chromatography ) GPC .

( 2 ) The basic properties of the products were studied and tested . The influence of the properties on the final structure was evaluated . The water solubility and dispersion particle size of WHBPU were measured by UV - vis and laser particle size analyzer .
The rheological behavior and crystallinity of WHBPU were measured by rotating rheometer , XRD and so on .
The differential scanning calorimetry ( DSC ) and TG ( TG ) analysis in thermodynamic tests show that the polymer increases with temperature , changes in morphology and molecular structure , and provides a basis for the evaluation of its phase structure and heat resistance .

( 3 ) UV - vis analysis shows that the WHBPU aqueous solution has the maximum absorbance at 220 nm , which shows that its terminal unsaturated group can absorb ultraviolet light curing . Under the action of 4 % Wt photoinitiator , four kinds of WHBPU are cured into thin film coating , the stability of emulsion , hardness , smoothness , water absorption , gel rate and curing process are studied , and the relationship between coating performance and molecular structure and segment ratio is summarized .

( 4 ) finally , according to the characteristics of the amphiphilic property of the WHBPU structure , the dye methylene blue small molecule is designed to be migrated to the chloroform phase experiment of the poor solvent , and the absorbance change of the maximum absorption peak in the migration methylene blue aqueous phase is characterized by UV - vis analysis , the small molecular weight of the migration is calculated , and the coating migration capability of the WHBPU is verified .

Through the above experimental design , structural characterization and property analysis ,

In the WHBPU synthesis process , the hyperbranched polyurethane structure was formed by the reaction of NCO with the terminal - OH of HBPs . The molecular weight trend of WHBPU was consistent with the design , but the molecular weight distribution was good .

WHBPU has good water solubility , and the solubility increases with the increase of hydrophilic group .
The crystallinity is consistent with the grafted MPEG , which is a spherulites structure , which causes the interaction between the crystal structure and the molecules to be destroyed , resulting in a sharp drop in viscosity and a characteristic of non - Newtonian fluid .
The temperature rise , the melting of the polymer , the thermal decomposition of the hard and soft segments occur at 310 鈩

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