| Abstract: | 嵌段式聚氨基甲酸酯(Segmented Polyurethane，SPU)是由軟質段與硬質段交替相連之的-(HS)n-型多團聯嵌段式共聚合物。PU因軟、硬質段可選擇之結構種類多，所擁有的化學結構種類相當多，加上其內部特殊的微相型態，反應出相當多變的性質；但也因此使得PU的型態、結構與性質間的關係複雜化。因此，我們藉由合成完全相分離的PU來探討此微區型態及型態變化的關係。 本實驗室過去在非極性PU的研究，發現由MDI-BD及cis-HTPB，且硬質段含量為55%所合成出相分離的非極性PU，由TEM觀察發現其型態為長圓柱狀(cylinder)或是平板狀(lamellar)。由此結果本實驗在硬質段中導入在側邊帶有巨大基團的分子去破壞其硬質段的平板結構。巨大基團能使主鏈的側邊產生具有1 nm的空間去影響硬質相的區域。PU的組成是由MDI、PolyIP、BD、bulky group進行兩階段溶液聚合法導入此巨大基團進行硬質段部份的改質，藉由添加不同量的巨大基團與硬質段含量的改變、搭配FT-IR、DSC、DMA及機械性質的分析，探討巨大基團對PU結構與性質的影響。 Segmented Polyurethane are linear block copolymers of the -(HS)n- type. Segmented polyurethane possesses enormous amount of chemical structures and its Micro-phase structure could react to form a variety of properties, hence it complicates its own as well. In order to probe into the mutual actions between its properties and compositions, we synthesize the nonpolar PU elastomer into a complete whole. Our previous research on nonpolar polyurethane, the experiment utilized better-performed phase-separated nonpolar-based PU, synthesized by MDI- BD, cis-HTPB and hard segment content 55%, direct observation the morphology by TEM, discover its shape was a long cylinder or lamellar form, which it’s in a regular state. With this in mind, add bulky group into Hard-segment, studying for the hard-segment of structure and properties. The structure-property relationships of a series of nonpolar segmented polyurethane(PU) with bulky side group were investigated. The bulky group is a molecule that can make a space about 1nm beside the backbone to interfere the hard segment domain. The PU based on 4,4-Diphenylmethane diisocyanate (MDI), polyisoprene(Poly-IP,MW 2500), 1,4-Butanediol (BD) and bulky group are synthesized by two-step solution polymerization. Hard-segment content (35,45,55,65 wt%) and bulky group contents (0,4,8,12 wt%) are varied and their effect on the properties are studied.Properties are studied by Fourier-Transform Infrared(FT-IR),Differential Scanning Calorimetry(DSC),Dynamic Mechanical Analysis(DMA) and tensile-strain testing. |
