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題名 | 二異氰酸鹽結構對聚氨基甲酸酯之結構--物性之影響=The Effect of Isocyanate Structures on the Properties of Polyurethane |
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作者 | 李大剛; 張芝慧; Lee, Da-kong; Chang, Chih-huey; |
期刊 | 宜蘭農工學報 |
出版日期 | 19960600 |
卷期 | 12 1996.06[民85.06] |
頁次 | 頁109-127 |
分類號 | 467.4 |
語文 | chi |
關鍵詞 | 二異氰酸鹽; 脂肪族; 芳香族; 對稱性; 極性; 結構之剛硬性; 結晶度; 相分離現象; Diisocyanate; Aliphatic; Aromatic; Symmetry; Polarity; Rigidity; Crystallinity; Phase separation; |
中文摘要 | PU為一泛用型之聚合物產品,一般型之PU產品多選用價廉之MDI及TDI(T80)為原 料。本文將探討一系列七種已工業化量產之二異氰酸鹽(分別為MDI、T100、T80、XDI、 IPDI、HMDI及HDI)之化學結構對成品物性及加工性之影響以擴展PU成品之開發與應用。 一系列PU彈性體利用上述之七種二異氰酸鹽與1,4-丁二醇反應為硬段,PTMEG(Mn= 2,000 g/mole)為軟段。用one-shot方法製造硬段含量40%之PU彈性體,其代號相對為 MDI-40,T100-40,T80-40,XDI-40,IPDI-40,HMDI-40及HDI-40供微分掃瞄熱卡計(DSC) 、動態一機械分析儀(DMA)、拉力實驗、熱重量分析儀(TGA)、折裂強度及硬度測試。同 時利用預聚合法方式合成固含量30%之樹脂供耐水解、厚度保持率及耐黃變等測試。用以探 討二異氰酸化學結構中之(1)對稱性(2)極性及(3)結構之剛硬性,對於PU成品的物性 以及用做合成皮原料時之相關加工特性之影響。用以開發不黃變PU特性樹脂、彈性體配方及 加工程序設計。 由DSC測試結果可知,此系列PU成品在-75∼-70℃之間均有一Tg(S)存在,受二異氰酸鹽化 學結構影響小,但其中以脂肪族結構之產品(HDI-40,HMDI-40及IPDI-40)有較低之Tg(S )。以對稱結構之二異氰酸鹽成品(MDI-40,HMDI-40及HDI-40)則易生成硬段結晶,其結 晶度大小依序為HDI-40,HMDI-40及MDI-40 隨其結構之剛硬性及立體障礙性之增加而減少, 另脂肪族二異氰酸鹽為基材之成品IPDI-40,HMDI-40及HDI-40均有軟段結晶Tm(S)之存在 。綜合以上觀測結果可知脂肪族二異氰酸鹽為基材製得之PU成品會有較佳之相分離現象。此 系列成品之DMA測試結果與DSC一致,另可知具有苯環結構及有較佳之對稱性結構者成品會有 較佳之高溫穩定性,故此系列成品以二者兼具之MDI有最佳之高溫穩定性。 此系列成品具有良好之機械性質,由拉力測試結果可之除HDI-40及HMDI-40二脂肪族對稱結 構者因結晶性高且較高之分子間作用力故成品較剛硬,其延伸率<1,000%,其餘成品之延 伸率均>1,000%。由耐水解測試結果可知,此系列成品之耐水解性均>92%主要受軟段結構 之影響,而較不受硬段組成改變之影響。而濕式合成皮加工之厚度保持率則受其樹脂之耐熱 性影響較大,其結果與TGA之測試結果相符,具有芳香族及對稱結構之MDI-40最佳。所有白 色合成皮成品在經由UV燈照射後可發現以脂肪族二異氰酸鹽基材之成品者除IPDI-40外均無 其變現象發生,而以芳香族二異氰酸鹽為基材之成品則因□化反應發生而出現黃變現象, IPDI-40成品耐熱性差由熱累積造成裂解之故。 |
英文摘要 | Polyurethane, PU, is a widely used polymer, most PU products adopt MDI and T80 as the raw material due to its lower cost. In this study a series of seven different commercialized diisocyanates (MDI, T100, T80,XDI, IPDI, HMDI and HDI) are used to investigate the effects of diisocyanate structure on the properties and process abilities to enhance PU applications. A series of PU elastomers were prepared by using seven different diisocyanates react with 1,4-BG as the hard segments and PTMEG (Mn = 2,000 g/mole) as the soft segments. Physical properties were examined by differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA), instron, thermal gravity analysis (TGA), tear strength and hardness measurements-Seven different 30% solid content PU resins were also prepared by prepolymer process for hydrolysis resistance and thickness maintenance and UV radiation test. The effects of diisocyanate structure including (1) sysmmetry (2) polarity and (3) rigidity on PU products' properties and process ability were investigated. From DSC affected results, all PU products show a Tg(S) at -75~-70℃ and is little by the diisocyanate structure. Aliphatic diisocyanatc-based PUs (HDI-40, HMDI-40 and IPDI-40) display lower Tg(S) than those aromatic diisocyanate-based materials. Symmetric diisocyanate-based materials (HDI-40, HMDI-40 and MDI-40) exhibit hard segment crystalline, the crystalline size was reduced by increasing the structure hidrance thus HDI-40 has larger crystalline size than HMDI-40 and MDI-40. PU specimens based on aliphatic diisocyanates (IPDI-40, HMDI-40 and HDI-40) exhibit soft segment crystalline melting temperature, Tm(S), therefore they show better phase separation than those based on aromatic diisocyanates. It can be also seen in DMA test results. From DMA study, MDI-40 exhibits the best high temperature stability due to the chain rigidity and structure symmetry. In this study, all PU specimens show good mechanical properties, except HDI-40 and HMDI-40 the rest specimens display elongation excess 1000%. The lower elongation of HDI-40 and HMDI-40 may be due to the larger hard segment crystalline size and intermolecular force. All PU specimens studied exhibit good hydrolysis resistance (>92%), this indicates hard segment structure has little effect on it. The thickness maintenance of wet process PU synthesis leather is mainly affected by high temperature stability at 120℃ (the drying temperature) of the resins. MDI-40 displayed the best thickness maintenance (95%), it's probably due to its chain rigidity and high degree of hard segment crystallinity. All aliphatic diisocyanate-based PU products showed no yellowing after UV radiation 72 hours exposure at 40℃ except IPDI-40, it caused by the thermal degradation instead of light unstability. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。