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

相關(guān)鏈接
聯(lián)系方式
  • 通信地址:長(zhǎng)春市前進(jìn)大街2699號(hào)
  • 郵編:130012
  • 電話:0431-85168022
  • 傳真:0431-85168022
  • Email:guansw@jlu.edu.cn
當(dāng)前位置:> 首頁(yè) > 論文著作 > 正文
35. Synthesis and properties of hyperbranched polyimides derived from tetra-amine and long-chain aromatic dianhydrides
作者:Shanyou Liu,Yunhe Zhang,Xueping Wang,Haiwei Tan,Ningnig Song,Shaowei Guan
關(guān)鍵字:hyperbranched polyimide
論文來(lái)源:期刊
具體來(lái)源:RSC ADVANCES,2015,5,107793-107803
發(fā)表時(shí)間:2015年
To investigate the properties of hyperbranched polyimides (HBPIs) for potential optical applications, novel fluorinated tetra-amine monomers with ether and sulfonyl groups, 4,4''''-di[3,5-di(2-trifluoromethyl-4-aminophenoxy) phenoxy] sulfone, and five kinds of long-chain dianhydrides, have been designed and synthesized. A series of anhydride-terminated hyperbranched polyimides have been prepared via a two-step method with chemical imidization. The HBPIs possess outstanding solubility and show excellent thermal and optical properties. The glass transition temperatures (T-g) of the HBPIs range from 230-242 degrees C determined by differential scanning calorimetry (DSC), and 232-263 degrees C by thermomechanical analysis (TMA), depending on the dianhydride used. The 5% weight loss temperatures are in the range of 480-533 degrees C, showing high intrinsic thermal-resistant characteristics of the HBPIs. The HBPI films show good optical transparency, higher than 80% at 800 nm. The cast polyimide films have favorable mechanical properties with tensile strengths of 91-112 MPa, elongation at break of 5.99-7.99%, and initial modulus of 2.14-2.57 GPa. The polyimides exhibit average refractive indices of 1.5780-1.6271, and birefringence of 0.0065-0.0079 because of the hyperbranched structure. The PI derived from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane possesses the lowest refractive indices due to the high fluorine content in the polymer chain.
主站蜘蛛池模板: 长子县| 华安县| 千阳县| 绥化市| 尼玛县| 襄樊市| 张家界市| 瑞昌市| 开封县| 紫阳县| 乌鲁木齐市| 彰化市| 文水县| 阳城县| 漳浦县| 宁夏| 固安县| 饶阳县| 施甸县| 通江县| 桑日县| 稷山县| 道真| 尉犁县| 宜川县| 和平县| 尉氏县| 清原| 东源县| 定襄县| 孟连| 元谋县| 瑞昌市| 正镶白旗| 绍兴县| 海兴县| 新绛县| 金川县| 镶黄旗| 东乡族自治县| 康平县|