Synthesis and Reactivity of Hydroxypoly(ethylene oxide) propyl–b–polydimethylsiloxane–b–propyl hydroxypoly(ethylene oxide)

A series of α, ω–bishydroxyl terminated PDMS, hydroxypoly(ethylene oxide) propyl–b–polydimethylsiloxane–b–propyl hydroxypoly(ethylene oxide) (HPEO–PDMS–HPEO) was prepared by a hydrosilation reaction of monoallyloxy substituted poly(ethylene oxide) with α,ω–bishydrogen terminated PDMS (HPDMS) that obtained via acid–catalyzed ring–opening polymerization of octamethylcyclotetrasiloxane with 1,1,3,3–tetramethyldisiloxane. Chloroplatinic acid was employed as the catalyst of hydrosilation. The molecular weight of HPEO–PDMS–HPEO could be controlled easily by varying the chain length of HPDMS. FTIR and ¹H–NMR spectroscopy were used to identify the structure of HPEO–PDMS–HPEO and HPDMS. The conversion of Si–H bond to Si–C bond was affected by the catalyst amount, reaction time and temperature. It was found that the optimum condition of hydrosilation reaction was the catalyst amount of 22 μg/g and 5 h time at 100°C. Synthesized HPEO–PDMS–HPEO showed good storage stability at ambient temperature. Urethane reaction of OH and NCO group revealed that HPEO–PDMS–HPEO was more reactive toward to diisocyanate than α, ω –bishydroxylbutyl terminated PDMS.     

Synthesis and characterization of fluorinated PEO-b-PDMS-b-fluorinated PEO by free radical addition

Fluorinated poly(ethylene oxide) propyl-b-polydimethylsiloxane-b-propyl fluorinated poly(ethylene oxide)(FPEO-b-PDMS-b-FPEO) was synthesized by a free radical addition of carbon-hydrogen of polyether segments of poly(ethylene oxide) propyl-b-polydimethylsiloxane -b-propyl poly(ethylene oxide)(PEO-b-PDMS-b-PEO) to hexafluoropropylene(HFP) using tert-butyl peroxypivalate as an initiator.In order to reduce the possibility of side reaction,the protection and deprotection via silylation were used for the end-...     

Functionalization of poly(1,3-dioxolane)

1,3-Dioxolane was polymerized in the presence of ethylene glycol in order to prepare α,ω-dihydroxylated polymers which, upon reaction with pluriisocyanates yielded networks swellable in water. The crosslinks were made of urethane groups, which are bulky and hydrophobic. In order to expand the scope of the networks that can be envisioned, we have studied the replacement of the two end-standing hydroxylic groups by unsaturated polymerizable groups. Several methods are presented which allow successfully the quantitative endowment of the polymer endings with methacryloyl- or styryl- or vinylether-type groups. α,ω-dihydroxylated poly(1,3-dioxolane) was also metallated and used as a macroinitiator for the polymerization of ethylene oxide: the α,ω-dihydroxylated triblock copolymer obtained is made of a central poly(1,3-dioxolane) block flanked by two poly(ethylene oxide) ones. Several methods are also shown to be efficient in the characterization of the hydroxylic end-standing functions of the polymer.     

Synthesis of polymer networks containing degradable polyacetal segments

Four different routes for the production of polyacetal containing networks are described : (1) free radical copolymerization of α,ω-(meth)acrylate terminated polyacetals, (2) hydrosilylation reactions of α,ω-allyl terminated poly- (1,3-dioxolane) with a multifunctional silane, (3) modification of α,ω-hydroxy terminated poly(1,3-dioxepane) through reaction with 3-isocyanatopropyl-triethoxysilane and subsequent cross-linking under influence of H₂O and (4) cross-linking of multifunctional hydroxy-terminated polyacetals by reaction with a diisocyanate.     

聚芳醚腈-聚硅氧烷嵌段共聚物的合成

采用4-烯丙基-2-甲氧基苯酚(Eugenol)为端基的聚二甲基硅氧烷与氟代苯端基含杂萘联苯结构聚芳醚腈,以碳酸钾为催化剂,二甲基亚砜与邻二氯苯为溶剂的条件下进行芳香亲核取代反应(SNAr),合成了一种高分子量的聚芳醚腈-聚硅氧烷嵌段共聚物,并采用FTIR和1H-NMR对该产物的结构进行了表征.DSC测试结果表明该类嵌段共聚物具有两个玻璃化转变温度(Tg),分别为-98～-90℃和255～287℃,而且共聚物具有优良的耐热性,10%的热失重温度(Td)在450℃以上.采用原子力显微镜和透射电镜观测发现该共聚物存在明显的相分离特征.     

Molecularly templated reaction for forming poly(dimethyl siloxane)–graphene oxide composite elastomers

This study explores the molecularly templated reaction of pyrene‐terminated telechelic poly(dimethyl siloxane) (PDMS) with graphene oxide (GO) to produce composite elastomers. These materials undergo chemical crosslinking between secondary amides near PDMS chain ends and epoxies on the surface of GO as confirmed by infrared spectroscopy, rheology, gel content, and mechanical property measurements. The incorporation of pyrene end groups introduces π–π interactions with GO surfaces that enhance the reaction efficacy of the nearby secondary amide groups. As a comparison, methoxy‐terminated telechelic PDMS containing the same secondary amides near the chain ends did not exhibit appreciable crosslinking with GO. Depending on the concentration of the amide groups, the pyrene‐terminated PDMS/GO elastomer can be highly crosslinked (e.g., up to 96 wt % gel) but highly extensible (e.g., extensional strains of more than 200%). This general strategy could be implemented using other amide containing polymers to produce a wide range of high‐performance thermosets and elastomers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1406–1413     

PDMS-b-PEO两亲性嵌段共聚物的合成及溶液性质

通过正丁基锂(n-BuLi)引发的六甲基环三硅氧烷(D3)阴离子开环聚合以及单硅氢封端聚二甲基硅氧烷(PDMS)与烯丙基聚氧乙烯醚(PEO)的硅氢加成反应, 合成得到了一系列分子量分布窄的PDMS-b-PEO两亲性嵌段共聚物. 利用凝胶渗透色谱(GPC)、傅里叶变换红外(FTIR)光谱、氢核磁共振谱(1H-NMR)表征了嵌段共聚物的结构组成. 通过表面张力仪测定得到了不同结构嵌段共聚物的平衡表面张力及临界胶束浓度(cmc). 结果显示, 该系列嵌段共聚物的cmc值不仅受到憎水性嵌段的影响, 同时也受嵌段共聚物的体积效应以及嵌段共聚物的几何形状(即嵌段共聚物各嵌段的比例)的影响, PDMS-b-PEO两嵌段共聚物的cmc值表现出了随憎水嵌段增加而相应增加的趋势. 通过透射电子显微镜(TEM)表征发现, PDMS-b-PEO嵌段共聚物在选择性溶剂水中会自组装形成球状、棒状以及囊泡状的聚集体.     

肝素化聚甲基硅氧烷-聚氧乙烯接枝物的合成及其体外抗凝血性能评价

以二甲基硅油接枝端羟基聚氧乙烯（ＰＤＭＳ ｇ ＰＥＯ ＯＨ）为基材，用二环己基碳二亚胺（ＤＣＣＩ）作脱剂，研究了羟基（ＯＨ）与肝素上的羧基（—ＣＯＯＨ）之间的脱水缩合反应，制备出肝素化的抗血栓材料ＰＤＭＳ ｇ ＰＥＯ Ｈｅｐ，并对其涂覆表面的肝素含量和体外抗凝血性能进行了初步评价．实验结果表明，肝素接枝的共聚物具有优良的抗凝血性能和一定的应用前景．     

Synthesis of novel moisture‐curable polyurethanes end‐capped with trialkoxysilane and their application to one‐component adhesives

Novel silane endcappers and novel polyurethanes end‐capped with trimethoxysilane (silylated polyurethanes) were developed as water‐curable materials in which the curing reaction occurred under humid conditions in the presence of dioctyltin diversatate as a curing catalyst. A variety of amine‐terminated trimethoxysilane compounds were synthesized by the Michael addition reaction of commercially available 3‐aminopropyltrimethoxysilane with acrylates, and the resulting silane endcappers were used to react with isocyanate‐terminated polyurethanes, providing the silylated polyurethanes. The moisture‐curable silylated polyurethanes were used for the preparation of novel one‐component and solvent‐free adhesives. The evaluated properties were the curing speed, the tensile shear bond strength, and the adherence to some substrates. The longer alkyl chains of the silane endcappers derived from various acrylates led to a slower curing speed, lower tensile strength at break, and longer elongation at break of the silylated polyurethanes. The tensile shear bond strength of the silylated polyurethane‐based adhesive decreased with decreasing the trimethoxysilane end‐capping ratio, whereas an increase in the adherence was observed. The adherence to the acrylic substrate was improved by changes in the main‐chain structure of the polyurethane based on the composition of poly(propylene oxide) and poly(ethylene oxide). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2689–2704, 2007     

Functionalized polymers with metal complexing segments: a simple and high‐yield entry towards 2,2′:6′,2″‐terpyridine‐based oligomers

Williamson type ether reactions were utilized for a high yield reaction of 4′‐chloro‐2,2′:6′,2″‐terpyridine with α,ω‐dihydroxy‐functionalized poly(ethylene oxide) and poly(oxytetramethylene)s to obtain bis(terpyridine)‐terminated telechelics. The completeness of the functionalization was proven by NMR spectroscopy, GPC and MALDI‐TOF‐MS investigations. The addition of transition metal ions resulted in a polyaddition polymerization leading to the formation of extended metallo‐supramolecular polymers, as proven by UV/VIS spectroscopy titration experiments.     

Binary blends based on poly(vinyl chloride) and multi-block copolymers containing poly(ϵ-caprolactone) and poly(ethylene glycol) segments

Binary blends based on poly(vinyl chloride) (PVC) were prepared both by casting from tetrahydrofuran (THF) and by mixing in the melt form, in a discontinuous mixer, PVC and multi-block copolymers containing poly(ϵ-caprolactone) (PCDT) and poly(ethylene glycol) (PEG) segments. PCDT-PEG copolymers were synthesized using a polycondensation reaction where the α,ω-bis-chloroformate of an oligomeric poly(ϵ-caprolactone) diol terminated (PCDT) and oligomeric PEG were employed as macromonomers. For comparison purposes, blends PVC with starting oligomers as well as with mixtures containing a typical low molecular plasticizer, dioctylphthalate (DOP), were also prepared. The copolymer miscibility was studied by differential scanning calorimetry (DSC) and FT-IR spectroscopy. The blend morphology was investigated by polarized light microscopy (PLM). A higher miscibility with PVC was observed for copolymers compared to PEG.     

Controlled synthesis of AB2 amphiphilic triarm star-shaped block copolymers by ring-opening polymerization

This paper describes the synthesis of a novel amphiphilic AB₂ triarm star-shaped copolymer with A = non-toxic and biocompatible hydrophilic poly(ethylene oxide) (PEO) and B = biodegradable and hydrophobic poly(ε-caprolactone) (PCL). A series of AB₂ triarm star-shaped copolymers with different molecular-weights for the PCL block were successfully synthesized by a three-step procedure. α-Methoxy-ω-epoxy-poly(ethylene oxide) (PEO-epoxide) was first synthesized by the nucleophilic substitution of α-methoxy-ω-hydroxy-poly(ethylene oxide) (MPEO) on epichlorohydrin. In a second step, the α-methoxy-ω,ω′-dihydroxy-poly(ethylene oxide) (PEO(OH)₂) macroinitiator was prepared by the selective hydrolysis of the ω-epoxy end-group of the PEO-epoxide chain. Finally, PEO(OH)₂ was used as a macroinitiator for the ring-opening polymerization (ROP) of ε-caprolactone (εCL) catalyzed by tin octoaote (Sn(Oct)₂). PEO-epoxide, PEO(OH)₂ and the AB₂ triarm star-shaped copolymers were assessed by ¹H NMR spectroscopy, size exclusion chromatography (SEC) and MALDI-TOF. The behavior of the AB₂ triarm star-shaped copolymer in aqueous solution was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM).     

Synthesis of rod-coil block copolymers via end-functionalized poly(p-phenylene)s

This paper describes a new way to synthesize rod-coil block copolymers consisting of poly(p-phenylene) (PPP) as rigid rod and either polystyrene (PS) or poly(ethylene oxide) (PEO) as flexible coil. The Suzuki-coupling of the AB-type monomer 4-bromo-2,5-diheptylbenzeneboronic acid (1) under strictly proton-free conditions leads to the control of PPP endgroups and hence allows the synthesis of a variety of differently end-functionalized poly(p-phenylene)s. The poly(2,5-diheptyl-p-phenylene)-block-polystyrene (7) is then prepared via condensation via condensation of anionically polymerized living polystyrene ( 6 ) with α-(4-formylphenyl)-ω-phenyl-poly(2,5diheptyl-p-phenylene) ( 4 ). Toluenesulfonic acid catalyzed condensation of α-methyl-ω-amino-poly(oxyethylene) ( 8 ) with PPP 4 yields poly(2,5-diheptyl-p-phenylene)-block-poly(ethylene oxide) ( 9 ).     

A Novel Route to α,ω‐Bis(acrylamidopeptide)‐Terminated Oligo(ethylene oxide) and Hydrogels

A new family of α,ω‐bis(acrylamidopeptide)‐terminated macromonomers were prepared via the ring‐opening addition of 4,4‐dimethyl‐2‐vinyl‐ and 2‐isopropenyl‐4,4‐dimethyl‐oxazol‐5‐on to α,ω‐diamine‐terminated poly(ethylene oxide). These macromonomers were used to produce hydrogels by means of thermally induced free‐radical polymerization. Swelling behavior and mechanical properties of the resulting hydrogels were influenced by the macromonomer type and the crosslinking density, as reflected by the equilibrium water uptake.     

Kinetic study of poly(ethylene oxide-b-2-methyl-2-oxazoline) diblocs synthesis from poly(ethylene oxide) macroinitiators

The synthesis of poly(ethylene oxide-b-2-methyl-2-oxazoline) (PEO-POXZ) block copolymers was carried out by the polymerization of 2-methyl-2-oxazoline (MeOXZ) from monomethoxy poly(ethylene oxide) macroinitiator. The initiating functions were 4-chloromethylbenzoate or tosylate groups. The functionalization of α-methoxy-ω-hydroxy PEO was optimized by adjustment of the reaction temperature. The duplication side reaction was investigated in the case of tosylate functionalization. The determination of the propagation rate constants of the MeOXZ polymerization showed that the presence of the PEO chains decreased the propagation rate constant in the case of active species under the form of oxazolinium ions, while it increased the propagation rate constant in the case of covalent active species, most probably by partial ionization.     

Facile synthesis and responsive behavior of PDMS‐b‐PEG diblock copolymer brushes via photoinitiated “thiol‐ene” click reaction

We present herein a mild and rapid method to create diblock copolymer brushes on a silicon surface via photoinitiated “thiol‐ene” click reaction. The silicon surface was modified with 3‐mercaptopropyltrimethoxysilane (MPTMS) self‐assembled monolayer. Then, a mixture of divinyl‐terminated polydimethylsiloxane (PDMS) and photoinitiator was spin‐coated on the MPTMS surface and exposed to UV‐light. Thereafter, a mixture of thiol‐terminated polyethylene glycol (PEG) and photoinitiator were spin‐coated on the vinyl‐terminated PDMS‐treated surface, and the sequent photopolymerization was carried out under UV‐irradiation. The MPTMS, PDMS, and PEG layers were carefully identified by X‐ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and water contact angle measurements. The thickness of the polydimethylsiloxane‐block‐poly(ethylene glycol) (PDMS‐b‐PEG) diblock copolymer brush could be controlled by the irradiation time. The responsive behavior of diblock copolymer brushes treated in different solvents was also discussed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Formation of polymer vesicles by amphiphilic fluorosiloxane graft copolymers in solution

Amphiphilic fluorosiloxane graft copolymers with a poly(dimethylsiloxane)(PDMS) backbone,a hydrophobic fluorosiloxane side-chain and three hydrophilic poiyether side-chains were synthesized by hydrosilation reaction in this work.The micellization of amphiphilic graft copolymers in the water/ethanol solvent system was investigated,and vesicles with different size were formed after the self-assembly system was aged for different time.     

Self-catalytic cross-linking reaction and reactive mechanism studies of α-aminomethyl triethoxysilanes for α,ω-dihydroxy poly(dimethylsiloxane)

Some kinds of aminomethyl triethoxysilanes, cross-linkers of α,ω-dihydroxy poly(dimethylsiloxane) (PDMS), can act as catalyst to self-catalyze the cross-linking reaction with PDMS, as found in our studies. Three kinds of α-aminomethylsilanes, [(diethyl)aminomethyl triethoxysilane (DMTS), anilinomethyl triethoxysilane (AMTS) and cyclohexylaminomethyl triethoxysilane (CMTS)], and two kinds of γ-aminopropyl silanes, [(γ-aminopropyl triethoxysilane (APTS) and (N-β-aminoethyl)-γ-aminopropyl triethoxysilane (AATS)] were selected to study the self-catalytic cross-linking reaction and its mechanism. The reactivity of the cross-linkers determined by n-hexane extraction experiments, was found to be DMTS > CMTS ? AMTS, but APTS and AATS could not react with PDMS without catalysis. The cross-linking degree was increased with the reactivity. The results of extraction experiments and Fourier transform infra-red (FT-IR) spectra indicated that the cross-linking reaction was an equimolar reaction between the Si-OH groups and Si-OC₂H₅ groups. Formation of electron conjugation of N and Si in α-aminomethyl triethoxysilane molecules has been proposed to elucidate the mechanism of the self-catalytic cross-linking reaction. The Modulated Differential Scanning Calorimeter (MDSC) results showed that the increase of the glass-transition temperature (T_g) of the cross-linked products was dependent on the reactivity of the cross-linkers. The thermo-gravimetric analysis (TGA) results demonstrated that the thermal stabilities of the cross-linked products were also related to the reactivity and the structures of the cross-linkers.     

Synthesis of ω‐phosphonated poly(ethylene oxide)s through the combination of kabachnik–fields reaction and “click” chemistry

The synthesis of new ω‐phosphonic acid‐terminated poly(ethylene oxide) (PEOs) monomethyl ethers was investigated by the combination of Atherton–Todd or Kabachnik–Fields reactions and the “click” copper‐catalyzed 1,3‐dipolar cycloaddition of azides and terminal alkynes. The Atherton–Todd route fails to give the corresponding phosphonic acid‐terminated PEOs due to competitive cleavage of the P? N bond during the dealkylation step. In contrast, the Kabachnik–Fields route leads with very good yields to ω‐phosphonic acid‐PEO through “click” reaction of azido‐PEO onto dimethyl aminopropargyl phosphonate prepared by Kabachnik–Fields reaction between propargylbenzylimine and dimethyl phosphonate, followed by acidic hydrolysis. The reported methodology, precluding the use of anionic polymerization of ethylene oxide, leads to novel well‐defined phosphonic acid‐terminated PEOs from commercially available products in good yields. Moreover, such a strategy can be adapted to anchor phosphonic acid functionality onto a wide range of polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Capillary zone electrophoretic analysis of positively charged poly(ethylene oxide) macromolecules using non-covalent polycation-coated fused-silica capillary and indirect UV detection

Capillary zone electrophoresis was used to show the coupling between NH2-terminated poly(ethylene oxide) and oligomers of lactic acid activated by transforming carboxyl chain ends to acyl chloride ones. The demonstration was based on the use of fused-silica capillary physically modified by pre-adsorption of polycations in the reversed polarity mode. As poly(ethylene oxide) macromolecules are UV transparent, indirect UV detection was used. A creatinine solution at pH 4.8 was selected as background electrolyte. Commercially available polycations with different structures were tested. It was shown that the reversed electroosmosis could be modulated according to the structure of the polycation. The method was then applied to analyse a commercial alpha,omega-diamino poly(ethylene oxide), namely Jeffamine ED 600 characterised by a broad mass dispersion. Data showed that the method can detect and separate amino poly(ethylene oxide) of different structures. When applied to analyse post coupling products, no free NH2-terminated poly(ethylene oxide) segments were detected. Moreover, the method allowed detection of water-soluble oligomers generated by partial degradation of lactic segments during the reaction.