2,2,6,6-四甲基-4-氧-哌啶氮氧自由基的阻聚及其同醌类化合物的协同效应

<正> 2,2,6,6-四甲基-4-氧哌啶氮氧自由基(TMPO)是六十年代后合成的一个新稳定自由基.这一物质可作类脂物的抗氧化剂,高分子材料的老化剂,它还被用作类脂、核酸、蛋白质、生物膜等生物高分子的新型自旋标记物,这已有专论叙述.另外TMPO对烯烃还有阻聚性质,如对丙烯酸类、苯乙烯.文献曾报道TMPO对苯乙烯、甲基丙     

用单一单体高效合成聚羟基丙烯亚胺树状高分子

报道了一种用丙烯胺为原料合成特丁基氧甲酰基(BOC)保护的氨基环氧丙烷(BN-PO),并用它作为唯一单体、利用氨基-环氧类点击反应/BOC脱保护的连续反应,高效合成内部含有羟基、外层含氨基的聚羟基丙烯亚胺树状高分子(HOPPI)的新方法.由于利用点击反应,只需少许过量单体即可使树状高分子接枝完全且只用正己烷沉淀即可除去过量单体.用核磁氢谱表征了各代树状高分子对应的化学位移,用质谱和凝胶渗透色谱验证合成树状高分子分子量的分布.该树状高分子具有合成简单、单分散、高密度双官能团的特点,可进一步进行功能化修饰.     

基于双锂法的炔基功能化热塑性弹性体的合成

苯乙烯-异戊二烯-苯乙烯三嵌段聚合物(SIS)是目前广泛使用的一种热塑性弹性体(TPE)材料, 建立高效、 精准、 普适的SIS功能化方法一直是提高TPE材料性能的关键. 首先, 利用双烯单体与单官能度引发剂的反应合成了双官能度的双锂引发剂; 然后采用双锂引发法, 以炔基功能化单体封端, 高效合成了α,ω-端炔基官能化SIS聚合物. 采用叔丁醇锂作为异戊二烯聚合段的调节剂, 叔丁醇钾作为苯乙烯聚合段的调节剂, 合成了低乙烯基结构含量(5.8%)、 窄分子量分布(<1.17)的SIS三嵌段聚合物; 再向SIS三嵌段聚合物中一步加入炔基官能化的1,1-二苯基乙烯(DPE)衍生物进行封端, 以高于90%的收率高效合成了α,ω-端炔基官能化SIS三嵌段模块聚合物, 借助炔基的高效点击反应, 实现了功能化及拓扑化TPE材料的制备.     

二茂钛/锡/环氧化合物引发苯乙烯活性自由基聚合的研究

采用单茂钛CpTiCl3和二茂钛金属化合物(n-BuCp)2TiCl2,引发剂4-甲氧苯基缩水甘油基醚(I1),1,4-丁二醇二缩水甘油基醚(I2),4,4′-亚甲基二(N,N-二缩水甘油基苯胺)(I4)和苯基缩水甘油基醚甲醛共聚物(I5)及还原剂Sn组成引发体系,引发苯乙烯活性自由基聚合,合成线型和多臂聚合物.探讨了不同茂钛金属化合物、引发剂和还原剂对苯乙烯聚合的影响;并采用13C-NMR和GPC对聚苯乙烯的结构和性能进行了表征.结果表明所得聚合物是无规聚苯乙烯,聚合物分子量高,分子量分布窄.聚合行为属于活性自由基聚合.     

末端为噻吩基的聚苯乙烯大分子单体的合成及其氧化偶联聚合

以丁基锂为引发剂、四氢呋喃为溶剂 ,在氮气气氛和 - 78℃下进行苯乙烯 (ST)阴离子聚合 ,并加入 3 溴噻吩作为终止剂 ,从而合成出末端含噻吩基的聚苯乙烯 (PST Thp) ,它可以进行氧化偶联聚合 ,是一类新的大分子单体 .在无水三氯化铁作用下 ,PST Thp可以进行均聚反应或与噻吩进行共聚反应 ,共聚反应生成主链刚性、支链分子量分布窄的聚 (噻吩 接枝 苯乙烯 ) (PThp g ST) ,凝胶渗透色谱、红外光谱和吸收光谱证实接枝共聚物的生成     

含胺基功能性单体的聚合研究——Ⅺ.甲基丙烯酸-2-羟基-3-吗啉基丙酯的合成及其聚合

<正> 一些含有吗啉基的高聚物,作为含脂肪叔胺基的医用高分子材料而被瞩目。我们曾报道了N-(N′-次甲基吗啉)取代丙烯酰胺的合成,及其在过氧化二月桂酰引发下的聚合动力学。它的聚合规律和我们以往所报道的含脂肪叔胺基单体的聚合一样。本文合成了在同—分子中既含吗啉基,又含有羟基的丙烯酸脂,即甲基丙烯酸-2-羟基-3-吗啉基丙酯(HMPMA),研究了在过氧化二月桂酰(LPO)引发下的热聚合,以及在芳香酮作增感剂下的光聚合。关于HMPMA的合成,虽有所报道,但关于其表征,在过氧化     

特殊形态接枝高分子颗粒的合成

表面接枝高分子微球具有分子结构的可设计性 ,分散稳定性好 ,被用于高效催化剂的载体、药物释放控制和疾病治疗等生物医学领域 ,因而引起了许多高分子材料和生物医学工作者的极大兴趣[1～ 3] .我们用链转移自由基聚合法合成了一端为苯乙烯基封端的聚乙二醇 ( PEG)和聚 ( N -异丙基丙烯酰胺 )等亲水性大分子单体 .在与疏水性单体如苯乙烯等的二元分散共聚反应中 ,利用接枝共聚物在溶液中的自组装 ,制备了粒径分布均一 ,颗粒表面形态光滑 ,同时表面具有功能性高分子链的微球 [4～ 8] .传统的合成高分子微球的研究主要是以苯乙烯或甲基丙烯酸…     

端基为巯基的聚己内酯的合成

以三氟甲烷磺酸亚锡为催化剂, 2-巯基乙醇为引发剂, 在温和条件下引发ε-己内酯的开环聚合, 得到端基为巯基的聚己内酯, 其分子量可控且分布较窄. 在此过程中, 巯基不需要保护而不会影响聚酯的结构, 当聚合温度升高时, 聚合物端基结构不发生改变, 但分子量分布变宽. 端基为巯基的聚己内酯能够通过偶合反应生成中间含二硫键的聚己内酯; 同时, 以2-羟乙基二硫化合物为引发剂合成得到分子中间含二硫键的窄分布聚己内酯, 经还原后也可得到端基为巯基的聚己内酯. 这两种方法条件温和, 效率较高, 具有良好的可控性.     

含氟光引发剂的合成及其性能研究

以2-羟基-4'-(2-羟乙氧基)-2-甲基苯丙酮(Irgacure 2959)和全氟辛酰氯(PFOC)为原料合成了光引发剂全氟辛酸-2-[4-(2-羟基-2-甲基丙酰)苯氧基]乙酯(2959-F),利用红外光谱(FT-IR)和核磁共振(¹⁹F NMR)对2959-F进行了结构表征;通过紫外吸收光谱测定了2959-F的紫外吸收谱;通过实时红外光谱(RT-IR)对合成的含氟光引发剂进行了光聚合反应动力学研究,考察了光强和引发剂浓度对单体的双键转化率和聚合速率影响,并研究了光引发剂2959-F的抗氧阻聚性能.结果表明:随着光强的增大,单体的双键转化率和聚合速率增加;在一定范围内,引发剂的浓度越高,双键转化率越高,聚合速率越快.2959-F具有较高的双键转化率和较快的聚合速率,并且具有较好的抗氧阻聚性.     

含磺酸基半乳糖高分子的合成及与凝集素相互作用研究

以含半乳糖的甲基丙烯酸羟乙酯和对苯乙烯磺酸钠为单体,通过可逆加成断裂链转移聚合设计合成了一系列具有不同结构的含糖高分子.采用核磁共振氢谱和凝胶渗透色谱对材料的结构进行了表征.分别通过比浊法和酶联免疫吸附实验,以花生凝集素(PNA)为模型,研究了磺酸基的数量及分布对材料与凝集素之间相互作用的影响.结果表明,磺酸基的引入能通过静电相互作用协同增强含半乳糖高分子与PNA之间的特异性结合作用,并且这一作用可通过磺酸基数量与排列方式进行调节,相对于嵌段共聚型材料,无规共聚型材料与PNA的结合作用更强,其中P(Gal21-r-SS41)与PNA的结合作用最强,较均聚半乳糖高分子(PGal)提高2.7倍.利用这种相互作用,材料能够通过阻断凝集素活性有效抑制肿瘤细胞的迁移,有望在临床抗肿瘤转移治疗中得以应用.     

Synthesis and evaluation of nitrated poly(4-hydroxystyrene) microspheres for pH sensing

Lightly crosslinked nitrated poly(4-hydroxystyrene) microspheres were prepared for pH sensing. The first step is to prepare poly(4-acetoxystyrene) microspheres using porous glass membrane emulsification followed by suspension polymerization. The resulting microspheres have diameters between 1 and 2 μm. They hydrolyzed to poly(4-hydroxystyrene) by exposing them to base. This is followed by nitration to nitric acid. The percentage of nitrogen depends on the nitration conditions. Percentages greater than the theoretical percentage for mononitro poly(4-hydroxystyrene) can be obtained at elevated temperatures indicating partial dinitration. These microspheres were cast into hydrogel membranes for use as pH sensors. The membrane is turbid because the refractive index of the microspheres is higher than the hydrogel refractive index. At high pH, deprotonation of the hydroxyl group introduces a negative charge onto the polymer backbone causing it to swell. Swelling is accompanied by a decrease in microsphere refractive index, which is detected as a decrease in membrane turbidity.     

Miscibility of poly(ε-caprolactone), a semicrystalline polymer,with amorphous poly(styrene-4-hydroxystyrene) copolymers

The miscibility of poly(ε caprolactone) (PCL) with poly(styrene-co-4-hydroxystyrene) (PHS) copolymers was investigated as a function of comonomer composition experimentally and with calculations by two models; the binary interaction model and the association model. PCL was found to be completely miscible with PHS copolymers containing 5 or more mole percent of 4-hydroxystyrene (HS) comonomer units for the entire range of blend compositions. Segmental interaction densities, B_ijs, were determined by the analysis of the equilibrium melting point depression and by the application of the binary interaction model. By correlating the segmental interaction energy densities with the binary interaction model, thermodynamic miscibility is for comonomer composition over five mole percent of 4-hydroxystyrene, which is in agreement with the experimental phase behavior. Application of the association model for specific interactions to blends also predicts the experimental miscibility boundary and phase behavior for all the PHS copolymers/PCL blends. © 1995 John Wiley & Sons, Inc.     

Glass transitions in hydrogen-bonded polymer complexes

Mutual precipitates of poly (N, N-dimethyl acrylamide) and poly (4-hydroxystyrene) were collected from dioxane, methanol, or acetone. The glass transition (T_g) temperatures of the precipitates are higher than the weight-average values. Clear films cast from dimethylformamide solutions have lower T_g values. Complexation also occurred between poly (ethyl oxazoline) and poly (4-hydroxystyrene) in dioxane and between poly (vinyl pyrrolidone) and poly (4-hydroxystyrene) in methanol. Again, the glass transition temperatures of the precipitates are higher than the values for the blend films. The ΔC_p values associated with the glass transitions of the complexes are smaller than those of the blends having the same compositions. Negative excess heat capacities of mixing have been observed for several precipitates.     

A morphological analogue of japanese lacquer. Grafting of p-hydroxystyrene onto pullulan by ammonium persulfate initiation in dimethylsulfoxide

Pullulan-g-poly(p-acetoxystyrene) ( I ) was prepared using ammonium persulfate (APS) as an initiator in dimethylsulfoxide (DMSO) solution. I was deacetylated by hydrazine hydrate to yield pullulan-g-poly(p-hydroxystyrene) ( II ). The degree of polymerization of the grafted poly(p-hydroxystyrene) chain ( III ) was 15–20. Despite the effective grafting (%), this method caused the degradation of pullulan. The number of branch polymer chains per pullulan molecule were evaluated to be 0.9 to 2.5 from number average molecular weights of the permethylated II and III . The glass transition temperature of II was higher than that of III , indicating that the polar hydroxyl groups of pullulan in the graft polymer caused an increase in the rigidity of the grafted polymer chains. Pullulan-g-poly(o-hydroxystyrene) and pullulan-g-poly(MMA) were also readily prepared by this method.     

Azide-Containing Phenolic Resin as a Negative Deep Uv Resist

A negative photoresist has been developed by partial esterification of poly(p-hydroxystyrene) with p-azidobenzenesulfonyl chloride. About 10% of esterification is sufficient to sensitize the polymer to light in the wavelength region between 240 and 300 nm. The dose required to insolubilize the polymer was 80 mJ/cm². The resolution capability is not as high as expected because of the swelling of photoinsolubilized resist films in an aqueous alkaline developer.     

Cationic polymerization behavior of hydroxystyrenes

Solution polymerizations of o-, m- and p-hydroxystyrene with boron trifluoride etherate were investigated. The results of infrared and ultraviolet spectroscopic investigations of the polymers thus obtained indicate that p-hydroxystyrene polymer consisted mainly of the structure formed through the normal vinyl polymerization mechanism, whereas o- and m-hydroxystyrene polymers contained considerable portions of the structures due to the reaction of the vinyl group with the phenol nucleus. The rate of polymerization and the intrinsic viscosity of the polymer decreased in the order p-hydroxystyrene ? o-hydroxystyrene > m-hydroxystyrene. It was of interest that on the cationic polymerization only p-hydroxystyrene gave polymer of high molecular weight. Plausible polymerization mechanisms were considered. Solid-state polymerization of p-hydroxystyrene at solid carbon dioxide temperature with the use of boron trifluoride etherate was also investigated. Appreciable polymerization occurred only at fairly high catalyst concentrations.     

Deep UV photoresists based on poly(dl-tert-butyl fumarate)

Poly(di-tert-butyl fumarate) was prepared and evaluated as a potential candidate as a deep UV photoresist. Although this polymer displayed excellent sensitivity, the polymer was found to exhibit poor dry etch resistance. Copolymers of di-tert-butyl fumarate with either allyltrimethylsilane or styrene, and an onium salt as a photoacid generator were synthesized and subsequently evaluated using a 248-nm KrF excimer laser step-and-repeat system (stepper). At 248 nm, the absorbance of ～ 1 μm thick resist films was only 0.156-0.211. The sensitivities of these resists were 1-4 mJ/cm². The dry etch resistance of these photoresists was comparable to that of conventional positive photoresists based on novolac resins. © 1995 John Wiley & Sons, Inc.     

Melting behavior,miscibility, and hydrogen-bonded interactions of poly(ε-caprolactone)/poly(4-hydroxystyrene-co-methoxystyrene) blends

The miscibility of poly(4-hydroxystyrene-co-methoxystyrene) (HSMS) and poly(ε-caprolactone) (PCL) was investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). HSMS/PCL blends were found to be miscible in the whole composition range by detecting only a glass transition temperature (T_g), for each composition, which could be closely described by the Fox rule. The crystallinity of PCL in the blends was dependent on the T_g of the amorphous phase. The greater the HSMS content in the blends, the lower the crystallinity. The polymer–polymer interaction parameter, χ₃₂, was calculated from melting point depression of PCL using the Nishi-Wang equation. The negative value of χ₃₂ obtained for HSMS/PCL blends has been compared with the value of χ₃₂ for poly(4-hydroxystyrene) (P4HS)/PCL blends. The specific nature, quantitative analysis, and average strength of the intermolecular interactions in HSMS/PCL and P4HS/PCL blends have been determined at room temperature and in the molten state by means of Fourier transform infrared spectroscopy (FTIR) measurements. The FTIR results have been in good correlation with the thermal behavior of the blends. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 95–104, 1998     

Rheology of poly(methyl methacrylate) Langmuir monolayers: percolation transition to a soft glasslike system

An experimental study of the equilibrium properties and of the surface rheology of Langmuir monolayers of poly(methyl methacrylate) (PMMA) at the air/water interface has been carried out as a function of polymer concentration (Γ) and molecular weight (M(w)). Dilational and shear complex elasticity moduli covering a frequency range from 10(-3) to 0.2 Hz have been discussed. It was found that the air∕water interface behaves as a poor solvent for PMMA monolayers, thus suggesting that the polymer coils take collapsed soft-disks (pancakes) shape at the interface. The equilibrium and dynamic results suggest a fluid-to-soft-glass transition as the polymer concentration increases above a critical packing fraction at constant temperature. This two-dimensional transition is in agreement with results previously discussed for the dilational rheology of poly(4-hydroxystyrene) [F. Monroy, F. Ortega, R. G. Rubio, H. Ritacco, and D. Langevin, J. Chem. Phys. 95, 056103 (2005)]. Furthermore, the Γ-dependence of the relaxation dynamics of the monolayers suggests that the gel state may be considered as a fragile soft glass.     

一种高感度深紫外正性化学增幅型抗蚀剂的制备

聚对羟基苯乙烯和环己基乙烯基醚反应得到缩醛保护的聚合物.该聚合物易溶于常见的有机溶剂,具有较好的热稳定性,在248 nm处透明性良好.该聚合物可与聚对羟基苯乙烯-甲基丙烯酸金刚烷基酯及二砜光产酸剂等组成一种三组分正性化学增幅型深紫外光致抗蚀剂,初步研究了该抗蚀剂的感光成像性能.采用KrF激光（248 nm）曝光,在较低的后烘温度下,显影得到分辨率为180 nm的线条图形.显影后的留膜率在99%以上.在光致抗蚀剂体系中引入对羟基苯乙烯-金刚烷基甲基丙烯酸酯共聚物,可提高光刻胶材料的玻璃化转变温度,有利于其实际应用.