Synthesis of functionalized linear poly(divinylbenzene). II. Synthesis of poly(divinylbenzene) with hydroxyl pendants and/or endgroups

Poly(divinylbenzene) [poly(DVB)] derivatives having hydroxyl terminals and/or pendants were synthesized by chemical modifications (hydration and hydroxylation) of unsaturated linear poly(DVB) ( I ), which was prepared by the polymerization of DVB catalyzed by acetyl perchlorate. Hydroboration of both terminal and in-chain carbon–carbon double bonds in I with BH₃.THF complex yielded a fully hydrated poly(DVB) II , in which hydrophilic and hydrophobic groups are placed alternately. Selective hydroboration of the vinyl endgroups in I with 9-borabicyclo[3.3.1]nonane led to an α,ω-dihydroxy-poly(DVB) ( III ). Reaction of I with m-chloroperbenzoic acid gave fully epoxidated poly(DVB) IV , which was subsequently hydrated to yield polymer V consisting of glycol repeat units and terminals. The physical properties and reactions (chain extension and crosslinking) of these polymers were also studied.     

锆基色谱填料的制备方法和物理化学性质

氧化锆基质色谱填料适合于碱性物质,特别是生物大分子的分离,因而具有良好的应用前景。它的制备方法对其物理化学性质有很大的影响,从而影响填料的色谱性能。该文对氧化锆微球的制备方法及其物理化学性质进行了综述。分析表明,目前氧化锆基质色谱填料的制备方法存在着难以克服的缺点,要制备理想的锆基色谱填料需要新的思路。     

正交试验法优化制备用于小分子物质分离的聚(甲基丙烯酸缩水甘油酯-二乙烯基苯)型整体柱

以甲基丙烯酸缩水甘油酯(GMA)为单体,二乙烯基苯(DVB)为交联剂,以环己醇和正十二醇为致孔剂,过氧化苯甲酰(BPO)为引发剂,直接以50 mm×4.6 mm色谱柱为模具,通过原位聚合制备聚(GMA-DVB)型整体柱。以GMA和DVB的体积比、环己醇和十二醇的体积比以及BPO占聚合物的质量分数为三因素,以分离苯和乙苯等小分子物质时的半峰宽分离度(R1/2)为考察指标,进行三因素三水平的正交试验,通过测定整体柱的比表面积、孔径和孔容分布对其进行表征。结果表明,制备整体柱的最优配方为V(GMA): V(DVB): V(环己醇): V(正十二醇)=0.825:0.825:1.32:2.03, BPO的质量分数为0.7%。应用所制备的整体柱分离苯和乙苯等小分子物质,理论塔板数达到37000塔板/m, R1/2值达到7.14,完全达到基线分离,分离时间小于10 min。该方法制备整体柱的重复性好,柱效较高,基本满足商品化要求。     

Liquid chromatography techniques for characterizing poly(Vinyl Alcohol)

Poly(vinyl alcohol) (PVOH) samples may contain several heterogeneities requiring the development of chromatographic techniques for characterization. Size exclusion separations have been carried out using a number of aqueous eluents, incorporating electrolyte, or electrolyte/organic modifier, or surfactant. The most favourable molecular size separation was obtained using 0.25% w/v sodium lauryl sulfate as eluent. Reasonable values for molecular weights of PVOH samples have been determined. Compositional distributions in copolymer systems can be assessed using high-performance liquid chromatography employing a reversed-phase separation mechanism. For poly(vinyl alcohol), gradient elution with water/tetrahydrofuran (THF) with a wide pore polystyrene-based packing produced separations dependent on degree of hydrolysis and sequence length distribution. The elution results were verified with a column packed with non-porous beads. Partially hydrolysed PVOH samples appeared to have a broad distribution of composition.     

SYNTHESIS OF MACROPOROUS COPOLYMER OF VCA AND DVB

The reactivity ratios of vinyl acetate(VAc) and divinyl benzene (DVB) were calculated from the Q and e values.The possibility of the copolymerization of these two monomers was predicted and the copolymerization was carried out by suspension polymerization technique in the presence of pore producing agent (toluene and gasoine).The relative ratio of acetoxy group and benzene ring in the copolymer were monitored by IR measurement during the polymerization.The variation of pore properties,such as spectific surface area,porosity and average pore diameter,with polymerization time were determined.The copolymers at various polymerization time were alcoholyzed and thus the variation of the hydroxyl group content with polymerization time was studied.     

Friedel–crafts reactions of pendant vinyl groups in macroporous monosized poly(meta‐divinylbenzene) and poly(para‐divinylbenzene) particles

Residual vinyl groups in macroporous monosized polymer particles of poly(meta‐DVB) and poly(para‐DVB) prepared with toluene and 2‐EHA as porogens have been reacted with aluminum chloride as Friedel–Crafts catalyst with and without the presence of lauroyl chloride. In the reaction between aluminum chloride and pendant vinyl groups a post‐crosslinking by cationic polymerization takes place. A reaction occurring simultaneously is the addition of HCl to the double bonds. The progress of these reactions was studied by characterization of vinyl group conversion, pore size distribution, specific surface area, morphology, and swelling behavior. In the reaction with aluminum chloride the poly(para‐DVB) particles showed a substantially higher conversion of pendant vinyl groups than the particles made of poly(meta‐DVB) independent of porogen type. The reaction with aluminum chloride led to a reduced swelling in organic solvents and an increased rigidity of the particles prepared with toluene as porogen. This is confirmed by an increase in the total pore volume in the dry state and a change in the pore size distribution of these particles. Also in the reaction with lauroyl chloride poly(para‐DVB) particles have shown a higher conversion of pendant vinyl groups than poly(meta‐DVB) particles and the acylation was almost complete at the early stage of the reaction. The swelling in organic solvents is reduced as a result of the incorporation of acyl groups into the particles prepared with toluene as porogen. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1366–1378, 2000     

致孔剂对HP（MA—VAc—MMA）载体孔结构的影响

以二乙烯苯和双丙烯酸多缩乙二醇酯为交联剂、聚醋酸乙烯酯（ＰＶＡｃ）或它与醋酸丁酯（ＢＡＣ）的混合物为致孔剂、ＢＰＯ为引发剂，用悬浮聚合随后水解的方法制得了部分水解聚（丙烯酸甲酯－醋酸乙烯酯－甲基丙烯酸甲酯）［ＨＰ（ＭＡ－ＶＡｃ－ＭＭＡ）］多孔载体，研究了ＰＶＡｃ及（ＰＶＡｃ＋ＢＡＣ）用量、分子量及混合比对ＨＰ（ＭＡ－ＶＡｃ－ＭＭＡ）孔结构的影响。结果表明，当ＰＶＡｃ的Ｍ＞２．５×１０５，ＰＶＡｃ／ＢＡＣ为２．３，用量为１０～２０％时，可制得孔隙率较高，孔径分布较窄，孔表面积较大的多孔载体。这种载体适用于微生物固定化。     

粒径可控的聚乙烯醇交联微球VA/DVB的制备

以醋酸乙烯酯(VAc)为主单体,二乙烯基苯(DVB)为交联剂,聚乙烯醇(PVA)为分散剂,采用悬浮聚合法制备了交联微球VAe/DVB.重点考察了分散剂用量、搅拌速率、油水两相比例、NaCl用量等因素对交联微球的形成及其粒度的影响.使用甲醇对微球VAc/DVB进行醇解反应,制得了聚乙烯醇交联微球VA/DVB.结果表明:交联微球VA/DVB的物理形态决定于前驱体微球VAc/DVB的形貌与粒径.在悬浮聚合体系中,分散剂用量、搅拌速率与油水两相比是影响交联微球制备的主要因素,当分散剂用量太少(<0.3%)、搅拌速率太慢(<200 r/min)与油水两相体积比太大(>l:4)时,共聚合体系中均不能发生成球过程.控制悬浮聚合的反应条件,可以制备出球形度好、粒径可调控的交联微球VA/DVB.影响醇解反应的主要因素是反应温度,适宜的温度是40℃,反应15 h醇解度可达92%.     

Synthesis of ellipsoidal hematite/silica/polymer hybrid materials and the corresponding hollow polymer ellipsoids

Ellipsoidal trilayer hematite/silica/poly(divinylbenzene) hybrid particles were prepared by distillation precipitation polymerization of divinyl benzene (DVB) in the presence of hematite/3-(methacryloxy)propyl trimethoxysilane (MPS)-modified silica (SiO(2)) core-shell particles as the seeds. The polymerization of DVB was performed in neat acetonitrile with 2,2'-azobisisobtyronitrile (AIBN) as initiator to coat the hematite/MPS-modified SiO(2) seeds through the capture of DVB oligomer radicals with the aid of a vinyl group on the surface of the hematite/MPS-modified silica core-shell particles in the absence of any stabilizer or surfactant. The other hematite/silica/polymer trilayer hybrid particles with different polarity and various functionality, such as hematite/silica/poly(ethylene glycol dimethacrylate) and hematite/silica/poly(divinyl benzene- co-methacrylic acid) could also be prepared by this procedure. Hematite/silica/poly( N, N'-methylenebisacrylamide) composite particles could be prepared with unmodified hematite/silica particles as seeds. Hollow poly(divinyl benzene) (PDVB) and poly( N, N'-methylenebisacrylamide) (PMBAAm) ellipsoids with movable hematite cores were subsequently developed after the selective etching of the silica midlayer in diluted hydrofluoric acid from hematite/silica/PDVB and hematite/silica/PMBAAm trilayer hybrids. Hollow PDVB ellipsoids were obtained by removal of the silica midlayer and hematite core of the trilayer hybrids with concentrated HF solution. The resultant trilayer hybrid particles and hollow polymer ellipsoids were characterized by transmission electron microscopy and vibrating sample magnetometer.     

Synthesis of polyester having pendent hydroxyl groups via regioselective dehydration polycondensations of dicarboxylic acids and diols by low temperature polycondensation

In this article, we describe the one‐step synthesis of polyesters having pendent hydroxyl groups by Lewis acid‐catalyzed, regioselective, dehydration polycondensations of diols (glycerol and sorbitol) and dicarboxylic acids [tartaric acid (TA) and malic acid (MA)] containing pendent hydroxyl groups, using low temperature polycondensation technique. Direct polycondensations of TA or MA and 1,9‐nonanediol catalyzed by scandium trifluoromethanesulfonate [Sc(OTf)₃] successfully yielded linear polyesters having hydroxyl functionality (M_n = ca. 1.0 × 10⁴). To demonstrate the reactivity of the pendent hydroxyl group, a glycosidation was performed. Poly(nonamethylene L ‐malate) showed significant higher biodegradability, compared with poly(nonamethylene L ‐tartrate) or poly(nonamethylene succinate). Stable poly(nonamethylene L ‐tartrate) emulsion could be prepared using poly(vinyl alcohol) as the surfactant, although emulsions consisting of poly(nonamethylene succinate) were unstable and phase‐separated within a few days. Furthermore, direct polycondensations of TA and diethylene glycol (DEG) or triethylene glycol (TEG) successfully produced water‐soluble polyesters having hydroxyl groups. This new polycondensation system may be extremely effective not only for advanced material design using functional monomers but also for effective utilization of biomass resources as chemical substances. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5747–5759, 2009     

Hydroxyl Functionalized Uniform‐Porous Beads,Synthesis and Chromatographic Use

Uniform‐porous poly(dihydroxypropyl methacrylate‐co‐ethylene dimethacrylate), poly(DHPM‐co‐EDM) particles were synthesized as an alternative packing material for reversed phase chromatography. In the synthesis, poly(glycidyl methacrylate‐ethylene dimethacrylate), poly(GMA‐co‐EDM) particles were obtained by a multi‐stage swelling and polymerization protocol, the so called “modified seeded polymerization”. For this purpose, 2.4 µm polystyrene seed particles were first swollen by dibutyl phthalate (DBP) and then by a monomer mixture including glycidyl methacrylate and ethylene dimethacrylate. The repolymerization of monomer phase in the swollen seed particles provided porous uniform particles approximately 7 µm in size. Poly(DHPM‐co‐EDM) particles were obtained by the acid hydrolysis of the particles synthesized with different GMA feed concentrations. These particles were used as column‐packing material in the reversed phase separation of alkylbenzenes. The retention factor‐acetonitrile concentration diagrams clearly showed that the polarity of packing material could be controlled by changing the GMA feed concentration in the “modified seeded polymerization”. The packing materials with more hydrophobic character (i.e., poly(EDM) and poly(DHPM‐co‐EDM) particles produced with the GMA feed concentrations up to 20%) exhibited better chromatographic performance in the reversed phase mode.     

Mn2(CO)10‐induced controlled/living radical copolymerization of vinyl acetate and methyl acrylate: Spontaneous formation of block copolymers consisting of gradient and homopolymer segments

The controlled/living radical polymerization of vinyl acetate (VAc) and its copolymerization with methyl acrylate (MA) were investigated in bulk or fluoroalcohols using manganese complex [Mn₂(CO)₁₀] in conjunction with an alkyl iodide (R? I) as an initiator under weak visible light. The manganese complex induced the controlled/living radical polymerization of VAc even in the fluoroalcohols without any loss of activity. The R? I/Mn₂(CO)₁₀ system was also effective for the copolymerization of MA and VAc, in which MA was consumed faster than VAc, and then the remaining VAc was continuously and quantitatively consumed after the complete consumption of MA. The ¹H and ¹³C NMR analyses revealed that the obtained products are block copolymers consisting of gradient MA/VAc segments, in which the VAc content gradually increases, and homopoly(VAc). The use of fluoroalcohols as solvents increased the copolymerization rate, controllability of the molecular weights, and copolymerizability of VAc. The saponification of the VAc units in poly(MA‐grad‐VAc)‐block‐poly(VAc) resulted in the corresponding poly(MA‐co‐γ‐lactone)‐block‐poly(vinyl alcohol) due to the intramolecular cyclization between the hydroxyl and neighboring carboxyl groups in the gradient segments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1343–1353, 2009     

Estimation of distribution of vinyl groups in micron-sized monodisperse polymer microspheres by bromine titration method

The distribution of vinyl groups in polystyrene/poly(styrene-divinylbenzene) (PS/P(S-DVB)) composite microspheres produced by seeded copolymerization of S and DVB in the presence of 2.1-m monodisperse PS seed particles was estimated from the amount detected with bromine titration method as a function of the reaction time under various conditions.Part CXXIII of the series Studies on Suspension and Emulsion.     

Synthesis of functionalized linear poly(divinylbenzene). III. Synthesis of polymeric delocalized carbanion of poly(divinylbenzene) and its reactions

A polymeric delocalized carbanion of poly(divinylbenzene) [poly(DVB)] (2) was obtained by the proton abstraction with alkyllithium from the acidic methine moieties (H_A) of linear poly(DVB) (1) , which was prepared by the polymerization of DVB initiated by acetyl perchlorate. The formation of polyanion 2 was confirmed by UV–visible spectroscopy (λ_max = 630 nm) and the reaction with methyl iodide to give methylated poly(DVB). Delocalized polyanion 2 reacted with various electrophilic reagents in THF at 60°C, to yield poly(DVB) derivatives having pendant trimethylsilyl, vinyl, vinyloxyl, hydroxyl, and carboxyl groups. Proton abstraction with base and subsequent reactions with electrophiles were also studied with the linear unsaturated dimer of styrene (1,3-diphenyl-1-butene), as a model for poly(DVB) 1 .     

Preparation and biodegradation of sugar-containing poly(vinyl acetate) emulsions

To accelerate the biodegradability of poly(vinyl acetate)-based emulsions, emulsion copolymerizations of vinyl sugars, including triacetylated N-acetyl-D-glucosamine (GlcNAc)-substituted 2-hydroxyethyl methacrylate (GlcNAc(Ac)3-substituted HEMA), glucose-substituted HEMA (GEMA) and 6-O-vinyladipoyl-D-glucose (6-O-VAG) with vinyl acetate (VAc), were carried out using poly(vinyl alcohol) as an emulsifying agent in the presence of poly[(butylene succinate)-co-(butylene adipate)] [poly(BS-co-BA)]. Copolymerization with GEMA produced a stable emulsion and that with 6-O-VAG also produced a homogeneous emulsion. Their biodegradation tests indicated that PVAc main chain scission was accelerated by copolymerization with vinyl sugars.     

Preparation of hydrophobic interaction chromatographic packings based on monodisperse poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads and their application

The monodisperse, poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads with macroporous in the range of 8.0-12.0 microm were prepared by a single-step swelling and polymerization method. The seed particles prepared by dispersion polymerization exhibited good absorption of the monomer phase. The pore size distribution of the beads was evaluated by gel permeation chromatography and mercury instrusion method. Based on this media, a hydrophobic interaction chromatographic (HIC) stationary phase for HPLC was synthesized by a new chemically modified method. The prepared resin has advantages for biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery and good resolution for proteins. The dynamic protein loading capacity of the synthesized HIC packings was 40.0 mg/ml. Six proteins were fast separated in less than 8.0 min using the synthesized HIC stationary phase. The HIC resin was firstly used for the purification and simultaneous renaturation of recombinant human interferon-gamma (rhIFN-gamma) in the extract solution containing 7.0 mol/l guanidine hydrochloride with only one step. The purity and specific bioactivity of the purified of rhIFN-gamma was found more than 95% and 1.3 x 10(8) IU/mg, respectively.     

Poly(vinyl acetate‐co‐dibutyl maleate) latex films in the presence of grafted and post‐added poly(vinyl alcohol)

We describe the synthesis and characterization of a series of poly(vinyl acetate‐co‐dibutyl maleate) [P(VAc‐DBM)] latex particles (monomer molar ratio 10.6:1). One set of samples [high‐M and M_250k SDS‐P(VAc‐DBM), gel content 50% and 0%] was prepared in the presence of an anionic surfactant sodium dodecyl sulfate. The other two sets of samples [high‐M and M_250k PVOH–P(VAc‐DBM)] were prepared in the presence of poly(vinyl alcohol) (PVOH). These polymers differ in gel content (50 and 0%) and the extent of PVOH grafting (30 and 15%). Polymer diffusion across cell boundaries in the latex films was monitored by fluorescence resonant energy transfer (ET) experiments. First, we examined M_250k samples in the presence of grafted and post‐added PVOH. The presence of post‐added PVOH (5%) causes a small but detectable retardation on the rate of polymer diffusion, whereas the presence of grafted PVOH (degree of grafting: 15%) significantly promotes the polymer diffusion rate. For the high‐M P(VAc‐DBM), the presence of post‐added PVOH also retards the polymer diffusion. Strikingly, the presence of grafted PVOH (degree of grafting: 30%) in the high‐M PVOH‐P(VAc‐DBM) promotes the polymer diffusion to such an extent that the diffusion was complete in the freshly prepared films. Our data also suggest that under our experimental conditions, the rate of P(VAc‐DBM) diffusion increases with an increase of the degree of PVOH grafting. To confirm these results, we carried out fluorescence microscopy experiments to monitor the fate of PVOH in these latex films and found that in newly formed PVOH–P(VAc‐DBM) films, the PVOH was either uniformly distributed in the P(VAc‐DBM) matrix or the domains were too small to be resolved (i.e., < 0.5 μm). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5005–5020, 2004     

Production of micron-sized monodispersed cross-linked polymer particles having hollow structure

4 μm-sized monodispersed cross-linked polymer particles having hollow structure were produced as follows. First, 1.7 μm-sized monodispersed polystyrene (PS) seed particles produced by dispersion polymerization were dispersed in ethanol/water (7/3, w/w) solution in which divinylbenzene (DVB), benzoyl peroxide (BPO), poly(vinyl alcohol), and toluene was dissolved. The PS seed particles were swollen with DVB, toluene and BPO maintaining high monodispersity throughout the dynamic swelling process where water was slowly added continuously. And then, the seeded polymerization of the (toluene/DVB)-swollen PS particles was carried out.     

Synthesis of tri-layer hybrid microspheres with magnetic core and functional polymer shell

Tri-layer magnetite/silica/poly(divinylbenzene) (Fe₃O₄/SiO₂/PDVB) core-shell hybrid microspheres were prepared by distillation precipitation polymerization of divinylbenzene (DVB) in the presence of magnetite/3-(methacryloxyl)propyl trimethoxysilane (MPS) modified silica core-shell particles as seeds. The polymerization of DVB was performed in neat acetonitrile with 2,2′-azobisisobutyronitrile (AIBN) as initiator to coat magnetite/MPS-modified silica particles through the capture of DVB oligomers with the aid of vinyl groups on the surface of inorganic seeds in absence of any stabilizer or surfactant. Other magnetite/silica/polymer tri-layer hybrid particles, such as magnetite/silica/poly(ethyleneglycol dimethacrylate) (Fe₃O₄/SiO₂/PEGDMA) and magnetite/silica/poly(ethyleneglycol dimethacrylate-co-methacrylic acid) (Fe₃O₄/SiO₂/P(EGDMA-co-MAA)) with various polarity and functionality, were also prepared by this procedure. Magnetite/silica/poly(N,N′-methylenebisacrylamide-co-methacrylic acid) (Fe₃O₄/SiO₂/P(MBAAm-co-MAA)) were synthesized with unmodified magnetite/silica particles as seeds. The resultant tri-layer hybrid particles were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), dynamic light scattering, and vibrating sample magnetometer (VSM).     

Organometallic‐Mediated Alternating Radical Copolymerization of tert‐Butyl‐2‐Trifluoromethacrylate with Vinyl Acetate and Synthesis of Block Copolymers Thereof

Organometallic‐mediated radical polymerization (OMRP) has given access to well‐defined poly(vinyl acetate‐alt‐tert‐butyl‐2‐trifluoromethacrylate)‐b‐poly(vinyl acetate) and poly(VAc‐alt‐MAF‐TBE) copolymers composed of two electronically distinct monomers: vinyl acetate (VAc, donor, D) and tert‐butyl‐2‐trifluoromethacrylate (MAF‐TBE, acceptor, A), with low dispersity (≤1.24) and molar masses up to 57 000 g mol⁻¹. These copolymers have a precise 1:1 alternating structure over a wide range of comonomer feed compositions. The reactivity ratios are determined as r _VAc = 0.01 ± 0.01 and r _MAF‐TBE = 0 at 40 °C. Remarkably, from a feed containing >50% molar VAc content, poly(VAc‐alt‐MAF‐TBE)‐b‐PVAc block copolymers are produced via a one‐pot synthesis. Such diblock copolymers exhibit two glass transition temperatures attributed to the alternating and homopolymer sequences. The OMRP of this fluorine‐containing alternating monomer system may provide access to a wide range of new polymer materials.