以聚脲为囊壁薄荷素油微胶囊的制备及表征

采用界面聚合法,以薄荷素油为芯材,以异佛尔酮二异氰酸酯为壁材单体,在催化剂四甲基乙二胺作用下和水反应形成聚脲外壳,制备出了薄荷素油微胶囊.通过扫描电镜、激光粒度分析仪、傅里叶红外光谱仪及热重分析仪分别对香精微胶囊的表面形貌、粒径分布、单体反应情况和热稳定性进行了分析表征.通过紫外可见分光光度计对香精微胶囊包覆率进行了测定.并分析了均质化速率和微胶囊平均粒径的关系以及不同乳化剂种类和芯壁比条件下微胶囊的形貌特征.结果表明,微胶囊平均粒径随均质化速率的增大而减小,下降到1μm左右时趋于平稳,当乳化剂采用聚乙烯醇且芯壁比为4∶1时,微胶囊形貌最佳,为规整球形.最终测得微胶囊芯材包覆率为84.09 wt%,粉末状微胶囊样品含油率为72.64 wt%,并且微胶囊芯材具有良好的热稳定性.     

Linear polybiurets: Facile synthesis and characteristic properties

Linear polybiurets have been synthesized by polyaddition of benzyloxyamine and diisocyanates, and properties of the novel polymeric materials have been elucidated. Prior to polymerization, model reactions between benzyloxyamine and phenyl isocyanate were examined in detail and proved to be controlled by the molar ratio of reagents and by catalysts to give the urea (1:1 adduct) and/or biuret (1:2 adduct). Under appropriate conditions, the biuret was synthesized in a quantitative yield. Polymerization of equimolar amounts of benzyloxyamine and diphenylmethane or hexamethylene diisocyanate proceeded smoothly to give polybiurets with inherent viscosities up to 0.52 dL/g. The benzyl group of the model biuret and polybiuret could be removed by catalytic hydrogenation. Both the N-benzyloxy-type and N-hydroxy-type polybiurets showed excellent solubility in common organic solvents. The two kinds of polybiurets as well as model biurets adsorbed metal cations efficiently. The N-hydroxybiuret structure exhibited particularly high affinity for iron(III) and was useful for selective removal of iron from metal cation mixtures. © 1996 John Wiley & Sons, Inc.     

二氧化碳—环氧丙烷—甲苯二异氰酸酯的三元共聚

二氧化碳和环氧丙烷(PO)在阴离子配位催化剂,如二乙基锌和等摩尔的水作用下,可接式(1)发生共聚。但产物聚丙撑碳酸酯(PPC)的热稳定性较差。改进途径之一是在反应中引入甲苯二异氰酸酯(TDI)进行三元共聚。本文报导在双金属阴离子配位催化剂PBM存在下合成一种热稳定性优于PPC的聚碳酸酯聚氨酯(PCPU)的研究结果(式2)。     

Clickable polyurethanes based on s‐triazine ring containing aromatic diisocyanate bearing pendent alkyne group: Synthesis and postmodification

A new s‐triazine ring containing aromatic diisocyanate bearing a pendent alkyne group, namely, 2,4‐bis(4‐isocyanatophenoxy)?6‐(prop‐2‐yn‐1‐yloxy)?1,3,5‐triazine was synthesized and reacted with various diols viz., 1,10‐decanediol, tetraethylene glycol and polyethylene glycols in the presence of dibutyltin dilaurate as the catalyst to obtain a series of linear polyurethanes. The selected polyurethanes possessing pendent alkyne groups were postmodified with chemically diverse azides viz., 1‐(azidomethyl)benzene, 1‐(azidomethyl)pyrene, and methoxy end‐caped poly(ethylene glycol) azide via copper‐catalysed azide‐alkyne Huisgen 1,3‐dipolar cycloaddition. FTIR and ¹H NMR spectra indicated quantitative click reaction. UV–vis and fluorescence spectroscopic analysis confirmed complete incorporation of pyrenyl groups indicating the formation of fluorescence active polyurethane by postmodification with 1‐(azidomethyl)pyrene. TG analysis of polyurethanes indicated two stage weight loss and their thermal stability, as judged by T ₁₀ values, was governed by weight percent of urethane linkages. The water contact angle measurements revealed improved wettability with increased content of PEG either in the backbone of polyurethanes or as grafted chains. DLS and TEM studies confirmed that certain polyurethanes possessing PEG segments displayed self‐assembly in aqueous solution, which was further supported by pyrene encapsulation studies using UV–vis spectroscopy. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1008–1020     

Spectral manifestation of the interaction of polyurethane components with oxide groups

The spectral-structural characteristics of polyurethane compositions with antipyrene fillers were investigated by a method of IR spectroscopy. The changes revealed in the vibrational spectra can be caused by intermolecular interaction of oligoether and diphenylmethane diisocyanate with aluminum-, boron-, and phosphor-containing compounds.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 133–135, January–February, 2005.     

扩链法合成聚乳酸类生物降解材料

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、二恶唑淋类扩链剂的合成进展。参考文献37篇。     

四甲基苯二甲基二异氰酸酯基水性聚氨酯的合成和性能

采用四甲基苯二甲基二异氰酸酯、聚酯二元醇和二羟甲基丙酸为原料,合成了一系列具有不同异氰酸根与羟基摩尔比（n(-NCO)/n(-OH)）的聚氨酯乳液。 研究了n(-NCO)/n(-OH)对水性聚氨酯性能的影响。 结果表明,当该比值增加时,乳液的粒径增大,分布变宽,结晶性降低,耐热性下降,耐水性能呈现降低的趋势。 当异氰酸根与羟基摩尔比为3时,四甲基苯二甲基二异氰酸酯基水性聚氨酯的乳液粒径为10～30 nm,膜的分解温度达到275 ℃,24 h吸水率低于10%。     

三光气法合成间苯二亚甲基二异氰酸酯研究

采用无毒的三光气代替光气与间苯二甲胺反应,合成了间苯二亚甲基二异氰酸酯。考察了原料的摩尔比、反应温度、反应时间和氮气气速的影响。结果表明,间苯二甲胺和三光气的摩尔比为1.25∶1.0,用10m L·min-1的氮气连续通入反应体系,反应温度为130℃,反应时间为6.0 h,间苯二亚甲基二异氰酸酯的产率为80.65%。     

Hydrolyzable poly(ester-urethane) networks from L-lysine diisocyanate and D,L-lactide/ϵ-caprolactone homo- and copolyester triols

Bioabsorbable poly(ester-urethane) networks were synthesized from ethyl 2,6-diisocyanatohexanoate (L -lysine diisocyanate) (LDI) and a series of polyester triols. LDI was synthesized by refluxing L-lysine monohydrochloride with ethanol to form the ester, which was subsequently refluxed with 1,1,1,3,3,3-hexamethyldisilazane to yield a silazane-protected intermediate. This product was then phosgenated using triphosgene. Polyester triols were synthesized from D,L-lactide, ?-caprolactone, or comonomer mixtures thereof, using glycerol as initiator and stannous octoate as catalyst. Polyurethane networks were cured using [NCO]/[OH] = 1.05 and stannous octoate (0.05 wt %) for 24 h at room temperature and pressure and 24 h at 50°C and 0.1 mm Hg. LDI-based polyurethane networks were totally amorphous and possessed very low sol contents. Networks based on poly (D,L-lactide) triols were rigid (T_g ∽ 60°C) with ultimate tensile strengths of ～ 40–70 MPa, tensile moduli of ～ 1.2–2.0 GPa, and ultimate elongations of ～ 4–10%. Networks based on ?-caprolactone triols were low-modulus elastomers with tensile strengths and moduli of ～ 1–4 MPa and ～ 3–6 GPa, respectively, and ultimate elongations of ～ 50–300%. Networks based on copolymers displayed physical properties consistent with monomer composition and were tougher than the networks based on the homopolymers. Tensile strengths for the copolymers were ～ 3–25 MPa with ultimate elongations up to 600%. Hydrolytic degradation under simulated physiological conditions showed that D ,L -lactide homopolymer networks were the most resistant to degradation, undergoing virtually no change in mass or physical properties for 60 days. ?-Caprolactone-based networks were resistant to degradation for 40 days, and high-lactide copolymer-based networks suffered substantial losses in physical properties after only 3 days. © 1994 John Wiley & Sons, Inc.