试验以壳聚糖为成膜主材料,甘油作为增塑剂,氯化钙作为交联剂,纳他霉素作为抗菌防腐剂,对以上4种成分分别进行单因素试验,通过考察膜的厚度、断裂伸长率、拉伸强度、透光率、透水性和水溶性等性能,确定壳聚糖、甘油、氯化钙和纳他霉素的最佳添加量.结果表明:由2％ 的壳聚糖,1％ 的甘油,0.3％ 的氯化钙和0.01％ 的纳他霉素所组成的壳聚糖复合膜综合性能最优.

为了改善聚乳酸(PLLA)的组织相容性及细胞亲和性,提高盐酸乌拉地尔生物利用率,文中在催化剂4-(二甲胺基)吡啶与N,N'-二环己基碳酰亚胺共同作用下,将含亲水基团的碱性聚电解质壳聚糖(CS)与PLLA共聚,制备了聚乳酸-壳聚糖接枝共聚物(PLCS),采用溶剂挥发法制备盐酸乌拉地尔PLCS微球并对其结构进行了表征,同时对微球的包封率和药物释放进行了测试.通过有机相加入乙醇的方法可以提高微球对药物的包封率.结果表明,当无水乙醇与三氯甲烷的体积比为1∶2时,制得的微球包封率最高,达到34.86％.体外药物释放结果表明,PLCS微球具有明显的缓释作用,其释药动力学满足Higuchi方程.

Here we report the synthesis of two novel phenylene-based polymers-poly(3,6-thienophenanthrene) (PTP36) and poly(2,7-thienophenanthrene) (PTP27) via base-free Suzuki–Miyaura reaction. The structure and electroluminescent properties of the meta-linked PTP36 and para-linked PTP27 are fully characterized. The obtained polymers were found to be liquid-crystalline, with broad band gap of 2.72eV and 2.49eV, respectively, which are much smaller than those of corresponding polyphenanthrenes. On the basis of PTP36 and PTP27, copolymers of 2,7-thienophenanthrene and 3,6-thienophenanthrene with 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzothiadiazole (DBT), namely PTP36-DBT and PTP27-DBT were prepared and be investigated as a potential donor material for polymer solar cells. The preliminary data show that the maximal power conversion efficiencies (PCEs) of the PTP27-DBT- and PTP36-DBT-based polymer solar cells are 3.5% and 0.9%, respectively.

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTHighly Efficient and Stable Deep Blue Light Emitting Poly(9,9-dialkoxyphenyl- 2,7-silafluorene): Synthesis and Electroluminescent PropertiesJun Wang†, Chang-qing Zhang†, Cheng-mei Zhong‡, Su-jun Hu‡, Xue-yi Chang§, Yue-qi Mo*†, Xiwen Chen*⊥, and Hong-bin Wu*‡View Author Information† Key Laboratory of Special Functional Materials, South China University of Technology, Guangzhou 510640, P. R. China‡ Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China§ Canton Oledking Optoelectronic Materials Co., ltd, Guangzhou 510640, P. R. China⊥ CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, VIC 3168, Australia*Corresponding authors. E-mail: [email protected] (Y.M.); [email protected] (H.W.); [email protected] (X.C.).Cite this: Macromolecules 2011, 44, 1, 17–19Publication Date (Web):December 15, 2010Publication History Received27 October 2010Revised5 December 2010Published online15 December 2010Published inissue 11 January 2011https://pubs.acs.org/doi/10.1021/ma102446bhttps://doi.org/10.1021/ma102446brapid-communicationACS PublicationsCopyright © 2010 American Chemical SocietyRequest reuse permissionsArticle Views1808Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Conjugated polymers,Differential scanning calorimetry,External quantum efficiency,Polymers,Thermogravimetric analysis Get e-Alerts

Starting from cheaper D,L-lactic acid(D,L-LA),lower molecular weight poly(D,L-lactic acid)(PDLLA) was directly synthesized via melt polycondensation.And then,using PDLLA as prepolymer,and 2,4-toluylene diisocyanate(TDI) as chain extender,poly(D,L-lactic acid)s biodegradable material was synthesized through diisocyanate chain extension in melt state.Catalyzed by SnCl_2,under the chain extension conditions,including NCO/OH molar ratio 1.0,temperature 160℃ and time 60min,viscosity-average molecular weight(M_η) of chain extension product dissolvable in chloroform could be 3.42 times higher than before.The structure of the product extended by TDI was characterized with FTIR and()~1H NMR.And the chain extension product(TDI-PDLLA) had higher glass transition temperature(Tg),melting temperature(Tm),and crystallinity than prepolymer PDLLA.However,cross-linking by-products with worse solubility in chloroform was apt to be produced once the reaction temperature was higher,or the reaction time was longer, or the molar ratio of NCO/OH was bigger.The existence of more cross-linking by-products made the Tg and crystallinity of TDI-PDLLA decrease.

Starting from cheaper D,L-lactic acid (D,L-LA), lower molecular weight poly(D,L-lactic acid) (PDLLA) was directly synthesized via melt polycondensation.By using PDLLA as prepolymer, 2,4-toluylene diisocyanate (TDI) as chain extender, and tetrahydrofuran (THF) as solvent, poly(D,L-lactic acid)s biodegradable material was synthesized through diisocyanate chain extension in solution state.When using different precipitators to terminate the solution chain extension, the solubility in chloroform,viscosity-average molecular weight (Mη), structure, and heat properties of chain extension products were different.Before precipitation, the reaction mechanism of chain extension in solution state was similar to that in the melt state.However, different precipitators had different termination mechanisms.When precipitated by metchanol, the reaction between residual NCO group and OH group in metchanol could keep the structure of product basically unchanged.When water was used instead of metchanol, the complex reaction between residual NCO group and water was apt to produce cross-linking products.

Starting from lower molecular weight poly(D,L-lactic acid)(PDLLA) produced by direct melt polycondensation of D,L-lactic acid(D,L-LA),poly(lactic acid) drug delivery material was synthesized through diisocyanate chain extension.Using isophorone diisocyanate(IPDI) as chain extender and tetrahydrofuran(THF) as solvent,the conditions for the chain extension synthesis were studied.Under the reaction conditions including NCO/OH molar ratio 2.0,reflux temperature 66 ℃ and reaction time 2 h,viscosity-average molecular weight(Mη) of chain extension product could be about 3 times higher than before.Compared with the chain extension of 2,4-tolylene diisocyanate(TDI) in solution state,the IPDI solution method had similar effect in increasing Mη under the mild conditions.More importantly,the novel IPDI chain extension method was advantageous to make the poly(lactic acid) drug delivery material with better physiological security than that by TDI chain extension method.

Starting from cheaper D,L-lactic acid(D,L-LA),lower molecular weight poly(D,L-lactic acid)(PDLLA) was directly synthesized via melt polycondensation.And then,using PDLLA as a prepolymer,isophorone diisocyanate(IPDI) as a chain extender,and tetrahydrofuran as a solvent,PDLLA-IPDI(Ⅰ) was synthesized through diisocyanate chain extension in solution state.Compared with chain extender 2,4-toluylene diisocyanate(TDI),IPDI had lower reaction activity,and the maxium viscosity-average molecular weight(Mη) of chain extension product dissolvable in chloroform under the similar chain extension conditions was slightly lower.Similar to the product PDLLA-TDI(Ⅱ),through direct melt polycondensation-diisocyanate chain extension by TDI in solution state,Ⅰ usually had higher glass transition temperature(Tg),melting temperature(Tm),and crystallinity than prepolymer(PDLLA).However,the alicyclic rigidity of the introduced IPDI segment was lower than the aromatic ring rigidity of the introduced TDI segment,T~~Ⅰ_g was correspondingly lower than T~~Ⅱ_g.

以乙醇酸为原料,在催化剂氯化亚锡质量分数0.5%,反应温度165℃,反应压力70 Pa,反应时间10 h的条件下进行熔融聚合,直接合成了生物降解的医用纤维材料聚乙醇酸(PGA),用IR,DsC,X射线衍射等进行了表征,并与乙交酯开环聚合二步法合成PGA进行了比较.直接熔融聚合PGA的结晶度和微晶尺寸高于二步法,其合成工艺流程短、简单易行、耗时少,有利于降低医用纤维材料PGA的开发成本.

Starting from lower molecular weight poly(D, L-lactic acid) (PDLLA) via direct polycondensation of D, L-lactic acid, polylactic acids drug delivery material was sgnthesized through diisocyanate chain extension. Using 2, 4- toluylene diisocyanate (TDI) as chain extender and tetrahydrofuran (THF) as solvent, the conditions for the chain extension synthesis were studied. Catalyzed by SnCl_2, under the reaction conditions including NCO/OH mol ratio 1.0 ～ 2.0, reflux temperature 65 ～ 66℃ and time 1 ～ 1.5h, viscosity-average molecular weight (M η) of chain extension product could be more than 3 times higher than before. Compared with the TDI chain extension in melt state, the solution method had more mild condition, which was more apt to control. The novel chain extension method also further increased the yield of polylactic acids drug delivery material starting from D, L-lactic acid.

通过正交试验探讨了聚乳酸直接熔融聚合工艺的最佳条件,即催化剂SnCl2用量0.5%,反应温度180℃,反应压力70 Pa,反应时间10 h.在上述条件下,分别以D,L-乳酸和L-乳酸的单体为原料,可得粘均相对分子质量为4 100的外消旋聚乳酸(PDLLA),以及粘均相对分子质量近10 000的聚左旋乳酸(PLLA).与通常使用高沸点溶剂和特殊装置进行共沸脱水的聚乳酸直接溶液聚合工艺相比,直接熔融聚合法设备和工艺简单,试剂用量少,产品的合成周期短,提纯方便,成本更低,在聚乳酸生物降解材料的开发方面更具有优势.

详细地综述了聚乳酸类生物降解材料的扩链法合成,特别是使用二异氰酸酯类、二口恶唑啉类扩链剂的合成进展.参考文献37篇.

以D,L-乳酸、乙醇酸为原料,通过熔融聚合法直接合成生物降解材料聚乳酸-乙醇酸(PLGA).在165 ℃、70 Pa下熔融聚合10 h,以w(SnCl2)=0.5%的氯化亚锡为催化剂时,特性黏数[η]最高可达0.2382 dL/g.当使用人体营养添加剂如乳酸锌、乳酸钙、乙酸锌、硫酸锌、牛磺酸等作为无毒催化剂反应时,[η]为0.1036～0.2150 dL/g.金属Lewis酸型催化剂乳酸锌与质子酸型催化剂牛磺酸复合使用,[η]为0.1068～0.1357 dL/g,比牛磺酸催化时(0.1036 dL/g)高,比乳酸锌催化时(0.1507 dL/g)低,未见明显的协同效果.简单易行的直接熔融聚合法,尤其是用无毒催化剂催化合成,有利于拓展PLGA在药物缓释领域的应用.

以L-乳酸单体为原料,通过熔融-固相聚合法直接合成聚左旋乳酸(PLLA).筛选出SnCl2为适宜的催化剂进行熔融聚合,聚合的最佳工艺条件为:SnCl2质量分数为0.5%,180 ℃、70 Pa下反应10 h.以熔融聚合制得的粘均相对分子质量为5 000的PLLA为原料,于60 Pa下,以SnCl2为催化剂进行变温固相聚合(先在135 ℃下反应5 h,再在150 ℃下反应10 h),可使粘均相对分子质量提高到反应前的5.3倍.

以D,L-乳酸单体为原料,使用人体营养添加剂如乳酸锌、乳酸钙、乙酸锌、硫酸锌、牛磺酸等作为无毒催化剂,通过熔融聚合直接合成低分子量的生物降解材料外消旋聚乳酸(PDLLA),粘均分子量接近4000.以PDLLA为载体,应用于制备抗菌药物环丙沙星聚乳酸微球,用DSC和SEM表征其成球性能,载药微球体外缓释半衰期为31.9h,53.2h后累积释药百分率约为84.0%,具有明显的缓释作用.