私密直播全婐app免费大渔直播,国产av成人无码免费视频,男女同房做爰全过程高潮,国产精品自产拍在线观看

搜索:  
Aromatic poly(ether ester)s derived from a naturally occurring building block nipagin and linear aliphatic α,ω-diols  
Aromatic poly(ether ester)s derived from a naturally occurring building block nipagin and linear aliphatic α,ω-diols
資料類型: PDF文件
關(guān)鍵詞: Naturally  Occurring  Aromatic  Poly(ether  ester)  Nipagin  
資料大小: 1077k
所屬學(xué)科: 高分子化學(xué)
來源: 來源網(wǎng)絡(luò)
簡介:
Nipagin, the methyl ester of p-hydroxybenzoic acid, which is present naturally in campanulaceae and ericaceous plants, was used to prepare poly(ether ester)s. In this study, two nipagin-based aromatic dimethyl esters were synthesized via one-step simple nucleophilic substitutions with methyl chloroacetate and 1,4-dibromobutane, respectively. Subsequently, two series of poly(ether ester)s, PN1-us and PN2-us, were synthesized using linear aliphatic a, -diols (n = 2, 3, 4, 6, 10, 12) after optimizing the reaction conditions, like feed ratio, reaction catalyst, time and temperature. The synthesized poly(ether ester)s exhibit weight-average molecular weights (Mws) in the range of 9300–32 100 g mol1, together with dispersity (D) values between 1.5 and 1.8. 1H NMR, 13C NMR and FTIR spectroscopy were used to characterize their chemical structures. The thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results show that the nipagin-based poly(ether ester)s exhibit excellent thermal stability with the initial decomposition temperature above 350 C and a two-step degradation mechanism. Glass transition (Tg), melting and crystallization temperatures (Tm, Tc), and the corresponding melting and crystallization enthalpies (DHm, DHc) are closely related to the lengths of the a,u-diols. The Tg values show a decreasing trend with a gradual increase in a,u-diol length in both PN1-us and PN2-us. The crystallization behaviors were also studied by isothermal crystallization and wide-angle X-ray diffraction (WAXD). The crystallizability proves to be enhanced with a gradual increase in a,u-diol length in each series. The mechanical properties were studied using tensile assays and dynamic mechanical analysis (DMA), which show that the nipaginbased poly(ether ester)s feature excellent mechanical properties with elastic modulus and tensile strength values reaching 600–800 MPa and 10–35 MPa, respectively. Finally, the nipagin-based poly(ether ester)s feature excellent comprehensive performance and the renewable nipagin will broaden the thermoplastic spectrum and have practical applications in the field of polymeric materials.
上傳人: hukeling
上傳時間: 2021-01-12 13:58:37
下載次數(shù): 0
消耗積分: 0  
立即下載:
1人
1人
1人
友情提示:下載后對該資源進行評論,即可獎勵2分。
報告錯誤:  1.下載無效  2. 資料明顯無價值  3. 資料重復(fù)存在

相關(guān)評論 共有0人發(fā)表評論 更多評論
你還沒有登錄,無法發(fā)表評論,請首先 登錄 注冊
免責(zé)聲明:本站部分資源由網(wǎng)友推薦,來自互聯(lián)網(wǎng),版權(quán)屬于原版權(quán)人,如果不慎侵犯到您的權(quán)利,敬請告知,我們會在第一時間撤除。本站中各網(wǎng)友的評論只代表其個人觀點,不代表本站同意其觀點。
主站蜘蛛池模板: 德阳市| 滨州市| 双辽市| 黄石市| 康定县| 赞皇县| 江陵县| 安阳县| 云安县| 呼图壁县| 安岳县| 手机| 静乐县| 茂名市| 南木林县| 图们市| 巴彦淖尔市| 布尔津县| 冕宁县| 布拖县| 澄江县| 鹤庆县| 古浪县| 盈江县| 瑞昌市| 无棣县| 行唐县| 儋州市| 从江县| 金门县| 厦门市| 舒兰市| 宣化县| 同心县| 栾城县| 商城县| 宿松县| 隆子县| 海伦市| 吉木乃县| 郎溪县|