Radical polymerization approach for ring opened oxanorbornene anhydride based macromonomers

In this work, we synthesized end group functionalization of the cis-Norbornene-5-6-endo-dicarboxylic anhydride species via the ring-opening metathesis polymerization (ROMP) of oxanorbornene derivatives generated a chiseled poly(cis-Norbornene-5-6-endo-Dicarboxylic anhydride) acrylate macromonomer. Further, acrylate oxanorbornene based macromonomer further polymerized via reversible addition fragmentation chain transfer (RAFT) polymerization technique. Chain transfer is exhibited in the structure during the radical polymerizations so that free radical polymerization could also be used to comb structure copolymers with a PDI value below 1.2 with the help of acrylate oxanorbornene. Atomic force microscopy reveals the comb shape of branched polymer brushes structure. This method involves polymerizable end-group attachment to a macromonomer, and the backbone of the comb polymer is created in a second step of the polymerization. We believe that this kind of comb structured polymers can be considered for different biological applications.     

Synthesis of block copolymers having perfluoroalkyl and silicone‐containing side chains using diazo macroinitiator and their surface properties

The fluorosilicone block copolymers of poly(perfluoroalkylethyl acrylate)‐b‐poly(3‐[tris(trimethylsilyloxy)silyl] propyl methacrylates) (PFA‐b‐PSiMAs) having perfluoroalkyl and silicone‐containing side chains were obtained by three‐step synthetic approaches. In the first step, hydroxyl‐terminated poly(perfluoroalkylethyl acrylate) macromonomer (PFAM) was prepared by the free‐radical polymerization of perfluoroalkylethyl acrylate and 2‐mercaptoethanol. In the second step, PFAM initiator (PFAMI) was prepared from the condensation reaction of the hydroxyl‐terminated PFAM and 4,4′‐azobis‐4‐cyanopentanoic acid chloride (ACPC). ACPC was obtained from the reaction of 4,4′‐azobis‐4‐cyanopentanoic acid and phosphorus pentachloride. In the third step, PFA‐b‐PSiMAs (BPFSs) were synthesized from the reaction of PFAMI macroinimer and SiMA. Fourier transform infrared spectroscopy and ¹H‐NMR analyses verified that the syntheses of ACPC, hydroxyl‐terminated PFAM, PFAMI, and BPFS were completed successfully. The intrinsic surface energies of BPFSs and their surface modification effects on poly(vinyl chloride) film were investigated by analyzing the surface free energies and atomic compositions of the outermost layer of the surfaces. BPFSs exhibit extremely low surface free energies of about 9.7–13.0 dynes/cm. It was confirmed that BPFS, having extremely low surface free energy, is preferentially enriched at the outermost layer of the surface of BPFS/poly(vinyl chloride) blend. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1917–1926, 1999     

Characterization and thermal properties of poly(n‐butyl acrylate‐g‐styrene) graft copolymers

Poly(butyl acrylate‐g‐styrene) graft copolymers were prepared by free‐radical polymerization using a polystyrene macromonomer carrying a methacryloyloxy group at the chain end and they were characterized by size‐exclusion chromatography, and Fourier transform infrared spectroscopy. Glass transition temperatures and degradation behavior were determined by thermal analysis. Only a single glass transition temperature was observed for the resulting graft copolymers, indicating the miscibility between the poly(styrene) phase and poly(butyl acrylate) (pBA) phase in the graft copolymer. The incorporation of polystyrene segments in the graft copolymer improved the thermal stability of pBA and enhanced the apparent activation energy for the thermal degradation of pBA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 783–789, 2001     

Rapid synthesis of new block copolyurethanes derived from L‐leucine‐PEG in ionic liquids under microwave irradiation

This study concerns the synthesis of novel multi block polyurethane (PU) copolymers containing eco‐friendly segments, taking the advantage of ionic liquids (IL)s under microwave irradiation. For this, L ‐leucine anhydride cyclodipeptide (LAC) was prepared and then a new class of poly(ether‐urethane‐urea)s (PEUUs) was synthesized with two types of ILs, including room temperature imidazolium (RTIL)s and molten ammonium type ILs. ILs were used as reaction media and PUs were prepared via two‐step polymerization method. Polymerization reaction was also conducted under conventional heating method in N‐methyl pyrrolidone (NMP) as reaction solvent. In the first step, 4,4′‐methylene‐bis(4‐phenylisocyanate) (MDI) was reacted with LAC to produce isocyanate‐terminated poly(imide‐urea) oligomers as hard segment. Chain extension of the resulting prepolymer with polyethyleneglycol (PEG) of molecular weights of 400 (PEG‐400) was the second step to furnish a series of new PEUUs. These multiblock copolymers are optically active, thermally stable and soluble in amide‐type solvents. PEUUs prepared in ILs under microwave irradiation showed more phase separation and crystallinity than PEUU prepared under conventional method. Some structural characterization and physical properties of these PEUUs, prepared under different methods, are reported and compared. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and swelling behavior of thermosensitive IPN hydrogels based on sodium acrylate and N‐isopropyl acrylamide by a two‐step method

A series of interpenetrating polymer network (IPN) hydrogels having higher swelling ratio (SR) and thermosensitivity were synthesized from sodium acrylate (SA) and N‐isopropyl acrylamide (NIPAAm) by a two‐step method. A series of the porous poly(sodium acrylate ‐co‐1‐vinyl–2‐pyrrolidone) [poly(SA‐co‐VP)], (SV), hydrogels were prepared from acrylic acid having 90% degree of neutralization and VP monomer in the first step. The second step is to immerse the SV dried gels into the NIPAAm solution containing initiator, accelerator, and crosslinker to absorb NIPAAm solution and then polymerized to form the poly(SA‐co‐VP)/poly(NIPAAm) IPN hydrogels (SVN). The effect of the different molar ratios of SA/VP and the content of NIPAAm on the swelling behavior and physical properties of the SVN hydrogels was investigated. Results showed that the SVN hydrogels displayed an obviously thermoreversible behavior when the temperature turns across the critical gel transition temperature (CGTT) of poly(NIPAAm) hydrogel. The pore diameter distributions inside the hydrogel also indicated that the pore sizes inside the SVN hydrogels were smaller than those inside the SV hydrogels. At the same time, the more proportion of SA was added into the hydrogel, the larger pore diameter of the SV hydrogel was formed. The results also showed that the SR decreased with an increase of the VP content in the SV hydrogel and more obviously decreased in the SVN hydrogels. The SVN networks also showed stronger shear moduli than SV hydrogels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of block comb‐like copolymers P(A‐MPEO)‐block‐PSt

Amphiphilic block comb‐shaped copolymers, poly[poly(ethylene oxide) methyl ether acrylate]‐block‐polystyrene [P(A‐MPEO)‐block‐PSt] with PSt as a handle, were successfully synthesized via a macromonomer technique. The reaction of MPEO with acryloyl chloride yielded a macromonomer, A‐MPEO. The macroinitiator PSt capped with the dithiobenzoate group (PSt‐SC(S)Ph) was prepared by reversible addition–fragmentation transfer (RAFT) polymerization of styrene in the presence of benzyl dithiobenzoate, and used as macroinitiator in the controlled radical block copolymerization of A‐MPEO at room temperature under ⁶⁰Co irradiation. After the unreacted macromonomer A‐MPEO had been removed by washing with hot saturated saline water, block comb‐shaped copolymers were obtained. Their structure was characterized by ¹H NMR spectroscopy and gel permeation chromatography. The phase transition and self‐assembling behaviour were investigated by atomic force microscope and differential scanning calorimetry. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of fluorinated polyacrylate–cellulose acetate butyrate interpenetrating polymer networks

Fluorinated polyacrylates are highly hydrophobic and oleophobic. However, their poor mechanical properties prevent their development in many applications. Combination of a fluorinated polyacrylate network with a rigid cellulose acetate butyrate (CAB) network in an interpenetrating polymer network (IPN) architecture is an effective method for improving the mechanical properties of fluorinated polyacrylates. IPNs combining poly(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate) (polyAcRf6) with CAB were prepared according to an in situ polymerization/crosslinking synthesis. CAB was crosslinked by addition between unmodified hydroxyl groups and the isocyanate of a pluri‐isocyanate crosslinker. The fluorinated network was obtained through free‐radical copolymerization of 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate with poly(ethylene glycol dimethacrylate). The rates of formation of both networks were followed using Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) of IPNs show a single glass transition temperature and a single mechanical relaxation temperature, which are characteristic of a high degree of interpenetration between the partner networks. The mechanical properties of IPNs are greatly improved compared with those of the single fluorinated network. CAB/polyAcRf6 IPNs were prepared, and characterized using DSC and DMTA as well as contact angle measurements for their surface properties. As hoped, the mechanical properties of such materials are much improved compared with those of the fluorinated partner alone. Copyright © 2010 Society of Chemical Industry     

Narrow‐disperse or monodisperse crosslinked and functional core–shell polymer particles prepared by two‐stage precipitation polymerization

Narrow‐disperse and monodisperse cross‐linked core–shell polymer particles containing different functional groups, such as esters, hydroxyls, chloromethyls, carboxylic acids, amides, cyanos, and glycidyls, in the shell layers in the micrometer size range were prepared by a two‐stage precipitation polymerization in the absence of any stabilizer. Commercial divinylbenzene (DVB), containing 80% DVB, was precipitation polymerized in acetonitrile without any stabilizer as the first‐stage polymerization and was used as the core. Several functional monomers, including methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2‐hydroxyethyl methacrylate, glycidyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, t‐butyl acrylate, i‐octyl acrylate, acrylic acid, acrylamide, acrylonitrile, styrene, and p‐chloromethyl styrene, were incorporated into the shells during the second‐stage polymerization. The resulting core–shell polymer particles were characterized with scanning electron microscopy and Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1776–1784, 2006     

Effect of crosslinker,buffer, and blending on damping properties of poly(styrene‐acrylonitrile)/poly(ethyl acrylate‐ n‐butyl acrylate) latex interpenetrating polymer networks

A series of poly(styrene‐acrylonitrile)/poly(ethyl acrylate‐n‐butyl acrylate) latex interpenetrating polymer networks (LIPNs) are synthesized by changing the kind of crosslinker and introducing a buffer. The results show that the crosslinker has an important effect on the damping properties of the LIPNs; divinylbenzene is the best crosslinker in the study. Moreover, introducing a buffer into LIPNs leads to an increase of the damping values over the temperature range where the damping value surpasses 0.5. The LIPN blend prepared by mixing LIPNs results in broadening of the damping peak, therefore improving the damping properties. Tests of the damping properties show that the LIPNs have good practical value. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2347–2351, 2002     

The effect of alkyd resins on the properties of AA‐NC semi‐IPNs as binders in wood finish

Wood coatings of AA‐NC semi‐interpenetrating polymer networks (semi‐IPNs), made from acid curing amino‐alkyd resins (AA) and nitrocellulose (NC), were prepared by sequential polymerization method. To investigate the effects of oil length on the properties of AA‐NC semi‐IPNs, three grades of alkyd resins (Alkyd) containing 38, 48, and 58% oil were synthesized with phthalic anhydride, glycerol, and soybean oil, employing alcoholysis method. The butylated urea formaldehyde resin (UF) and melamine formaldehyde resin (MF) were also prepared in this study. The AA‐NC semi‐IPNs were maintained at a weight ratio of AA : NC of 25 : 75, where the AA was the composition of MF : UF : Alkyd of 7.5 : 22.5 : 70 (by weight), and 10% of p‐toluene sulfonic acid solution (concentration, 25% in isopropyl alcohol) based on the weight of amino resins was added as acid catalyst. The properties of coatings such as viscosity, drying time, and gel time, and the properties of films including adhesion, hardness, abrasion resistance, impact resistance, tensile strength, released formaldehyde, lightfastness, solvent resistance, and durability were examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1923–1927, 2004     

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

To synthesize new functional poly(urethane‐imide) crosslinked networks, soluble polyimide from 2,2′‐bis(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride, 4,4′‐oxydianiline, and maleic anhydride and polyurethane prepolymer from polycaprolactone diol, tolylene 2,4‐diisocyanate and hydroxyl ethyl acrylate were prepared. Poly(urethane‐imide) thin films were finally prepared by the reaction between maleimide end‐capped soluble polyimide (PI) and acrylate end‐capped polyurethane (PU). The effect of polyurethane content on dielectric constant, residual stress, morphology, thermal property, and mechanical property was studied by FTIR, prism coupler, Thin Film Stress Analyzer (TFSA), XRD, TGA, DMTA, and Nano‐indentation. Dielectric constant of poly(urethane‐imide) thin films (2.39–2.45) was lower than that of pure polyimide (2.46). Especially, poly(urethane‐imide) thin films with 50% of PU showed lower dielectric constant than other poly(urethane‐imide) thin films did. Lower residual stress and slope in cooling curve were achieved in higher PU content. Compared to typical polyurethane, poly(urethane‐imide) thin films exhibited better thermal stability due to the presence of the imide groups. The glass transition temperature, modulus, and hardness decreased with increase in the flexible PU content even though elongation and thermal expansion coefficient increased. Finally, poly(urethane‐imide) thin films with low residual stress and dielectric constant, which are strongly affected by the morphological structure, chain mobility, and modulus, can be suggested to apply for electronic devices by variation of PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 113–123, 2006     

Synthesis of macromonomer from radical polymerization of styrene with a polymerizable photoiniferter

α‐(Methacrylyoxylethyloxycarbonylmethyl)‐ω‐(N,N‐diethyldithiocarbamyl)polystyrene macromonomers with different molecular weights were prepared by radical polymerization of styrene (St) using β‐methacryloxylethyl 2‐N,N‐diethyldithiocarbamylacetate (MAEDCA) as a polymerizable photoiniferter in toluene under ultraviolet light. The polymerization of St with MAEDCA carried out by a “living” process; that is, both the yield and the molecular weight of the resultant polymers increased with increasing of reaction time, and the resultant polymer was a macromonomer, for example, α‐(methacrylyoxylethyloxycarbonylmethyl)‐ω‐(N,N‐diethyldithiocarbamyl)polystyrene, designated as PSt‐macromonomer. The molecular weight of the PSt‐macromonomer depended on the concentrations of the polymerizable photoiniferter and St, as well as the conversion of St. The PSt‐macromonomer can copolymerize with MMA initiated by AIBN at 65°C to form a graft copolymer (PMMA‐graft‐PSt) with PSt branches randomly distributed along the PMMA backbone. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1350–1356, 2000     

Synthesis and characterization of sequential interpenetrating polymer networks of novolac resin and poly(ethyl acrylate)

Interpenetrating polymer networks (IPN) of Novolac/poly(ethyl acrylate) have been prepared via in situ sequential technique of IPN formation. Both full and semi IPNs were characterized with respect to their mechanical properties that is, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Physical properties of these were evaluated in terms of hardness, specific gravity, and crosslink density. Thermal behavior was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The morphological features were observed by an optical microscope. There was a gradual decrease in modulus and UTS, with consequent increases in elongation at break and toughness for both types of IPNs with increasing proportions of PEA. An inward shift and lowering (with respect to pure phenolic resin) of the glass transition temperatures of the IPNs with increasing proportions of PEA were observed, thus, indicating a plasticizing influence of PEA on the rigid, brittle, and hard matrix of crosslinked phenolic resin. The TGA thermograms exhibit two‐step degradation patterns. An apparent increase in thermal stability at the initial stages, particularly, at lower temperature regions, was followed by a substantial decrease in thermal stability at the higher temperature region under study. As expected, a gradual decrease in specific gravity and hardness values was observed with increase in PEA incorporation in the IPNs. A steady decrease in crosslink densities with increase in PEA incorporation was quite evident. The surface morphology as revealed by optical microscope clearly indicates two‐phase structures in all the full and semi IPNs, irrespective of acrylic content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Segmented polymer networks based on poly(N-isopropyl acrylamide) and poly(tetrahydrofuran) as polymer membranes with thermo-responsive permeability

Segmented polymer networks (SPNs) containing a polymer with a lower critical solution temperature were prepared by free radical copolymerization of poly(tetrahydrofuran) (PTHF) bis-macromonomers with N-isopropyl acrylamide (NIPAA). The PTHF bis-macromonomers, which were prepared by living cationic polymerization of tetrahydrofuran, were provided with acrylate or acrylamide end-groups by end-capping the living polymer chains with acrylic acid and 3-acrylaminopropanoic acid, respectively. Differential Scanning Calorimetry (DSC) experiments showed clearly that, for the same fractions of both network components, the phase morphology of the SPNs was highly influenced and adjustable by the nature of the end-groups of the bis-macromonomer as a result of their copolymerization behavior with NIPAA. For the same type of multi-component networks, the morphology changed from a heterogeneous up to a rather homogeneous nature by application of bis-macromonomers with, respectively, acrylate or acrylamide end-groups during their preparation. Swelling and DSC experiments on the swollen SPNs revealed, respectively, that the swelling properties and the cloud point temperature (T_cp) could be controlled by the network composition. The thermo-responsive water permeability and the possible application of the SPNs as pervaporation membranes for the separation of a water/isopropanol mixture were investigated as a function of temperature and network composition. The permeability and selectivity of the membranes decrease when the T_cp is reached. The permeability increases while the selectivity decreases with decreasing crosslink density or higher overall hydrophilicity of the SPNs.     

Block copolymerization by a cation to anion transformation process: 2. Polymerization of styrene by polyTHF possessing terminal secondary nitranions

A route for preparing block copolymers by a cation to anion transformation is examined. PolyTHF possessing a terminal secondary amine group is prepared by reacting living polymer with excess of the primary amine, then metallated with potassium to create a terminal nitranion. This is then used to initiate the anionic polymerization of styrene, but initiation is relatively slow and, although all the styrene is consumed, only about 30% of polyTHF chains form a block copolymer.     

芘核心第一代树状聚合物的合成与性能研究

以芘（Py）、丁二酸酐和甲醇为原料合成芘丁酸甲酯,然后与乙二胺发生酰胺化反应,进一步与丙烯酸甲酯进行迈克尔加成反应,得到芘为核心的第一代（G1．0）树状聚合物。热重分析结果显示,合成产物具有逐层热分解行为,最大分解温度为350℃左右。光学性能研究发现,合成产物荧光发射峰为427nm,发射波段为400—455nm,荧光发射波长红移趋于波长较长的区域,荧光性能较好。     

Synthesis and characterization of poly(methyl acrylate‐co‐itaconic anhydride)/TiO2 hybrid materials via sol–gel process

In the presence of 3‐aminopropyltriethoxysilane (APTES), the transparent and yellowish poly(methyl acrylate‐co‐itaconic anhydride)/TiO₂ [P(MA‐co‐Itn)/TiO₂] hybrid materials were prepared from the copolymer of methyl acrylate and itaconic anhydride [P(MA‐co‐Itn)] and tetrabutyl titanate (TBT) via a sol–gel process. At first, the triethoxysilane groups were incorporated into the copolymer P(MA‐co‐Itn) as pendant side chains by the aminolytic reaction between the itaconic anhydride units of the copolymer and the amino group of 3‐aminopropyltriethoxysilane (APTES), and then the covalent bonds between the organic and inorganic phases were introduced by the hydrolysis and polycondensation of the triethoxysilane groups on the copolymer with TBT. FTIR analysis proved the existence of the covalent bonds. The influences of APTES on glass transition and morphology of the hybrid materials was studied by differential scanning calorimetry, scanning electron microscope, and atomic force microscope. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1763–1768, 2000     

Effect of 3‐aminopropyltriethoxysilane on properties of poly(butyl acrylate‐co‐maleic anhydride)/silica hybrid materials

The transparent poly(butyl acrylate‐co‐maleic anhydride)/silica [P(BA‐co‐MAn)/SiO₂] has been successfully prepared from butyl acrylate‐maleic anhydride copolymer P(BA‐co‐MAn) and tetraethoxysilane (TEOS) in the presence of 3‐aminopropyltriethoxysilane (APTES) by an in situ sol–gel process. Triethoxysilyl group can be readily incorporated into P(BA‐co‐MAn) as pendant side chains by the aminolysis of maleic anhydride unit of copolymer with APTES, and then organic polymer/silica hybrid materials with covalent bonds between two phases can be formed via the hydrolytic polycondensation of triethoxysilyl group‐functionalized polymer with TEOS. It was found that the amount of APTES could dramatically affect the gel time of sol–gel system, the sol fraction of resultant hybrid materials, and the thermal properties of hybrid materials obtained. The decomposition temperature of hybrid materials and the final residual weight of thermogravimetry of hybrid both increase with the increasing of APTES. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the morphology of hybrid materials prepared in the presence of APTES was a co‐continual phase structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 419–424, 1999     

丙烯酸丁酯/VAE互穿聚合物乳液的研究

以互穿聚合物网络(IPN)方法合成丙烯酸丁酯与VAE共聚物乳液。研究了乳化剂、交联剂、溶胀时间、反应时间等条件对转化率的影响。以红外光谱、透射电子显微镜表征互穿共聚物乳胶膜的微观结构。通过吸水性及乳胶膜对水接触角的测定，证明其耐水性较VAE乳胶膜明显增强。。YEM照片表明互穿聚合物胶粒形态结构较VAE乳胶粒发生了明显变化。     

Modification of cellulose powder surface by grafting of polymers with controlled molecular weight and narrow molecular weight distribution

To modify cellulose powder surface, the grafting of polymers with controlled molecular weight and narrow molecular weight distribution onto the surface by the termination of living polymer cation with amino groups introduced onto cellulose powder surface was investigated. The introduction of amino groups onto cellulose powder surface was achieved by the treatment of cellulose powder with isatoic anhydride. It was found that cellulose powder having amino groups are readily reacted with living poly(2‐methyl‐2‐oxazoline) (polyMeOZO) cation, which was generated by ring‐ opening polymerization with methyl p‐toluenesulfonate as an initiator, and polyMeOZO with controlled molecular weight and narrow molecular weight distribution was grafted onto the surface. By the termination of living poly(isobutyl vinyl ether) (polyIBVE), which was generated by the polymerization with HCl/ZnCl₂ initiating system, with amino groups on cellulose powder, polyIBVE was also grafted onto the surface. The mole number of grafted polymer chain on cellulose powder surfaces decreased with increasing molecular weight of the living polymer cation, because of increasing steric hindrance with increasing molecular weight of living polymer cation. Wettability of cellulose powder surface to water was found to be controlled by grafting of hydrophilic or hydrophobic polymer onto the surface. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 515–522, 2000