Photo-induced orientation and micropattern imaging of maleimide copolymers containing azobenzene side groups

Photo-induced birefringence properties of azobenzene containing maleimide copolymers P[DR1PMI-co-St]1 and P[DR1MSt-co-PMI]2 are investigated. These polymers show reversible photo-induced birefringence and the rate parameters for the induction and relaxation processes are obtained. Photoimage patterns of the polymers with narrowest line width of 2 μm are obtained. The micro patterns are relatively stable for over a month at room temperature. Received: 12 September 1997/Revised version: 7 November 1997/Accepted: 17 November 1997     

New fluorescence active cellulosics prepared by a convenient acylation reaction

Novel, fluorescence active cellulosic polymers with high degree of functionalization of up to 1.0 were synthesized in homogeneous phase (cellulose in N,N-dimethylacetamide/LiCl and 6-O-thexyldimethylsilylcellulose in pyridine) with a mixed anthracene-9-carboxylic/p-toluenesulfonic acid anhydride. This novel and effective synthetic method yield the pure carboxylic acid esters of the polymers, which were characterized by means of FTIR- as well as ¹H and ¹³C NMR-spectroscopy. The polymers show typical fluorescence spectra, which are identical with the non-bond anthracene-9-carboxylic acid. Received: 26 August 1997/Accepted: 8 September 1997     

An investigation into the synthesis of polycarbazole squaraine derivatives

The polycondensation of squaric acid with 1,2-(9-Ethylcarbazol-3-yl)ethene and N-ethyliminostilbene in polyphosphoric acid yielded insoluble polymers which included substituted phosphate groups on the phenyl rings. The presence of phosphorus in these polymers was identified using solid-state ³¹P NMR and EDAX techniques. Furthermore the phosphate groups were not ionic, hence no charge-balancing anions were present. Both polymers did not electrically conduct but exhibited dielectric breakdown values of 0.1 and 0.06 MV cm⁻¹ respectively. Received: 16 December 1996/Revised: 10 March 1997/Accepted: 10 March 1997     

Grafting of side chain liquid crystal monomers onto polyethylene film

In order to obtain films of liquid crystalline polymers, a commercial polyethylene film was grafted with acryloyl chloride using γ-irradiation, and two tolane-containing alcohols were reacted with the chloride to obtain the corresponding acrylates. The morphology changes were studied by DSC, X-ray diffractometry and optical microscopy. The crystallinity of polyethylene films decreased by grafting, and mesophase with spherulites was observed over a wide temperature range. Received: 18 May 1997/Revised: 11 August 1997/Accepted: 13 August 1997     

Novel aprotic polar polymers 2. Miscibility of aliphatic polysulfoxides

Summary Miscibility of aliphatic polysulfoxides (1, 2) with other commodity polymers was examined by comparing glass transition temperature(s) (T_gs) of the mixture of these polymers with T_gs of the original polymers by differential scanning calorimetry. It was found that the aliphatic polysulfoxides had good miscibility with poly(2-methyl-2-oxazoline) or/and poly(N-vinylpyrrolidone). Received: 25 December 1997/Revised version: 23 February 1998/Accepted: 25 February 1998     

Effect of electrolyte on the emulsifier-free emulsion polymerization of vinyl acetate

The emulsifier-free emulsion polymerization of vinyl acetate was carried out in the absence or in the presence of some electrolytes such as sodium chloride, calcium chloride, aluminum chloride, sodium sulphate, and ammonium phosphate at 50°C using potassium persulphate—sodium bisulphite as a redox initiation system. The viscosity average molecular weights of the polymers obtained were also determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 711–715, 1997     

Study on polymerization of ethylenediaminetetraacetic acid and methyl methacrylate

The polymerization of ethylenediaminetetraacetic acid (EDTA) with methyl methacrylate(MMA) was prepared using a cerium(IV) redox initiator system at 60°C under nitrogen. The microstructures of the obtained polymers were characterized by NMR measurement and the DEPT technique, as well as by infrared spectroscopy. The mechanism of the polymerization reaction was determined from the microstructures of the derived polymers. It showed that the reaction leading to the polymerization formation was the carbon site of the ethylene of the EDTA. It was not the same as that suggested in the literature. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2311–2317, 1997     

Biocompatible α-aminoacids based aliphatic polyamides

Summary. Biodegradable aliphatic polyamides have been prepared from C10 and C14 dicarboxylic acids and amide-diamines containing one or two preformed amide linkages susceptible to enzymatic cleavage in their molecules. L-phenylalanine, either by itself or together with L-valine, was used to generated amide bonds which are cleavable by chimotrypsine. Improved chain flexibility and hydrophilicity of the polyamides was obtained using a triethyleneoxy based amide-diamine. Characterization of the novel monomers and polymers by FTIR and ¹H-NMR spectroscopy confirms the expected structures. Thermal data and solubility tests indicate that both T _m and solubility depend on the length and nature of the aliphatic segment present in the amide-diamine as well as on the "density" of interchain hydrogen bonds. Finally the polymers tested are capable of supporting fibroblast adherence and proliferation, and proved to be non cytotoxic. Received: 28 May 1997/Revised: 16 July 1997/Accepted: 16 July 1997     

Successive self-nucleation/annealing (SSA): A novel technique to study molecular segregation during crystallization

A new procedure to fractionate ethylene/α-olefin copolymers using DSC is presented. This procedure allows melt/melt and melt/solid segregation to occur during thermal cycles that promote self-nucleation, crystallization and annealing processes (Successive Self-Nucleation/Annealing, SSA). The SSA has been compared with the Step-Crystallization (SC) method proposed earlier in the literature to qualitatively characterize chain branching distribution in a faster and easier way than Temperature Rising Elution Fractionation (TREF). In general, SSA produces better fractionation than SC and the DSC derived chain branching distribution by SSA can be qualitatively comparable to that obtained by TREF. The SSA technique could have important applications for the characterization of polymers that crystallize over a broad temperature range. Received: 10 May 1997/Revised: 20 July 1997/Accepted: 6 August 1997     

Synthesis of triblock and random copolymers of 4-acetoxystyrene and styrene by living atom transfer radical polymerization

Triblock copolymers containing polystyrene (PSt) and poly(4-acetoxystyrene) (PAcOSt) segments have been prepared by atom transfer radical polymerization (ATRP). In the first step one of the two monomers was polymerized in bulk using the initiating system α,α′-dibromo-p-xylene/CuBr/2,2′-bipyridine (1/1/3). Subsequently the resulting telechelic polymers with active bromo end group structures were used as macroinitiators for the polymerization of the second monomer under ATRP conditions. This process gave PAcOSt-PSt-PAcOSt and PSt-PAcOSt-PSt triblock copolymers with predetermined molecular weights and narrow molecular weight distributions. Polymerization of a mixture of equal molar amounts of the two monomers yielded a random copolymer with narrow molecular weight distribution. Received: 25 June 1997/Revised: 25 August 1997/Accepted: 8 September 1997     

Transition temperature control of liquid crystalline poly(heptene sulphone)s

Liquid crystalline poly(heptene sulphone)s containing cholesteryl undecylenic ester and cholestanyl undecylenic ester were synthesized. The polymers displayed cholesteric mesophases during thermal transition. The clearing temperatures were from 114 to 172 °C depending on the molar ratio of mesogenic esters in the polymers. Received: 27 March 1997/Revised: 24 June 1997/Accepted: 27 June 1997     

刺激响应性聚合物的设计、合成及其应用研究新进展

介绍了研究刺激响应性聚合物的意义,针对水体系中的刺激响应性聚合物,介绍了近年来刺激响应性聚合物的设计与合成中的应用研究新进展,主要从3个方面进行阐述:①单一刺激响应性聚合物,包括温度、pH值、光、其他刺激响应性聚合物;②双重刺激响应性聚合物,包括温度-pH值、温度-光、温度-氧化还原刺激响应聚合物、pH值-氧化还原刺激响应聚合物;③多重刺激响应性聚合物,包括温度-光-pH值、温度-光-氧化还原、温度-pH值-CO₂刺激响应聚合物。着重评述了水体系中双重和多重刺激响应性聚合物的合成研究及应用。最后总结了多重刺激响应性聚合物应用研究的现状及问题,指出开发刺激响应性高度可控、灵敏度高、可逆性好的新型多重刺激响应性聚合物是未来的研究方向。     

Reversible redox behaviour of two electroactive polymethacrylates

Summary The radical melt polymerization of 2-[4-(6-methacryloyloxyhexa-1,6-diyloxy)phenylazo]-anthraquinone is described yielding the homopolymer p _m with the number average molecular weight (M _n ) of M _n =74kg/mol determined by gel permeation chromatography (GPC) using polystyrene (PS) calibration. The redox properties of a thin film of p _m were investigated by cyclic voltammetry. Two reversible redox waves were found at all applied sweep rates indicating two reversible electron (E) transfer processes of the anthraquinone units according the EE-mechanism. A thin film of the randomlike copolymethacrylate cp _r with the molar mass of M _n =73kg/mol was investigated, too. The sidegroups of cp _r are substituted by 77mol% with benzyl, by 22mol% with phenylazoanthraquinone and by 1mol% with COOH groups. The redox properties of cp _r depend on the timescale of the cyclovoltammetric experiment. At high sweep rates two reversible redox waves are observable corresponding to the EE-mechanism. At low sweep rates an additional reversible redox wave appears, which is essentially smaller than the other two. The third wave is explained to be a result of hydrogen bonding between the COOH groups and anthraquinone mono- and dianions. The most anthraquinone units are reduced according the EE-mechanism without hydrogen bonding due to statistical reasons. The reversible redox properties of p _m and cp _r are closely connected to their molar masses (M _n ≈75kg/mol), because both polymers have been previously obtained by radical solution polymerization yielding low molecular products with molar masses of M _n ≈10kg/mol. The low molecular polymers have shown an irreversible redox behaviour. Therefore, it could be demonstrated that the molar mass of an electroactive polymer significantly affects its redox properties. Received: 13 November 1998/Revised version: 30 March 1999/Accepted: 20 April 1999     

Synthesis of novel organoboron polymers by haloboration polymerization of bisallene compounds and their reactions

Summary. Novel organoboron polymers were prepared by haloboration polymerization of bisallene compounds. The polymers obtained have allylborane halide units in their main chain and can be expected as a novel type of reactive polymers. For example, the polymer prepared by haloboration polymerization between tribromoborane (1) and 1,2,10,11-dodecatetraene (2 b) was subjected to chain transformation reaction (dichloromethyl methyl ether rearrangement) to give the corresponding polyalcohol or polyketone. Haloboration-phenylboration polymerization of aliphatic bisallenes by using diphenylbromoborane also gave the corresponding polymers. Received: 8 July 1997/Revised: 23 July 1997/Accepted: 28 July 1997     

Electroactive and temperature‐sensitive hydrogel composites

The composites of the polypyrrole (PPy) and polyelectrolyte copolymers (PE) were prepared by electrochemical polymerization. The various compositions of the polyelectrolyte copolymers were used as a dopant, and were composed of copolymers of water‐soluble polymers and 2‐Acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS). Thermally sensitive (N‐isopropyl acrylamide, NiPAAm) and insensitive (acrylamide, AAm) polymers were used as the water‐soluble polymer. The electrochemical activity and mass change during the redox process of the PPy composites were investigated by potentiodynamic voltametry and electrochemical quartz crystal microbalance (EQCM). The mass change during the redox process was mainly concerned with the cation in the electrolyte solution. When the electrochemical activity of the PPy was larger than the amount of the polyelectrolyte anion (AMPS), the insertion/expulsion of the monoanion (ClO) into/from the PPy composite also occurred to ionically bond with the PPy in the redox process. The PPy/P(NiPAAm/AMPS) shows a significant mass decrease with increasing the temperature compared with the PPy/P(AAm/AMPS). The transition temperature of the PPy/P(NiPAAm/AMPS) is higher in the oxidized state than in the reduced state. The transition temperature of PPy composite increases with the composition of the hydrophilic electrolyte (AMPS). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 311–321, 1999     

Radical polymerization of acrylamide initiated by ceric ammonium nitrate-methionine redox initiator system

The polymerization of acrylamide, initiated by a cerium (IV) [Ce(IV)] ammonium nitrate-methionine redox initiator system, was carried out in an aqueous solution at different reaction conditions. The dependence of molecular weight and polymerization yield on the concentration of Ce(IV), polymerization time, and temperature was determined. The molecular weight distributions (MWD) of the resulting polymers were examined using the HPLC method. Based on the HPLC results, optimum reaction conditions were determined that provided an opportunity to obtain a polymer that had a narrow MWD. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1643–1648, 1997     

Electropolymerization of trimethylsilylphenols to silylated polyphenylene oxides and investigation of their properties. Enhanced conductivity of PPO by silyl group

Polymerization of o-, m-, and p-trimethylsilylphenols (TMS-phenols) was achieved electrochemically. The polymers were prepared as thin films on a platinum electrode and were found to be electroinactive in nonaqueous solutions. The polymers exhibited far higher conductivities than polyphenol or other substituted polyphenols. The conductivity of poly(p-TMS-phenol) was lower than that observed for the polymers of the o- and m-isomers. The polymers were characterized by infrared spectroscopy. The effect of monomer concentration, supporting electrolyte concentration, current densities, and temperature on the polymerization was investigated using microgravimetry. The observed empirical kinetics were as follows. The rates of polymerization of o-,m-, and p-TMS-phenol were found to be of 0.8, 0.8, and 0.7 order dependent on monomer concentation, of 0.5, 0.5 and 0.45 order dependent on electrolyte concentration, and of 0.9, 0.9 and 0.8 order dependent on current densities. By investigating the effect of temperature on electropolymerization, the corresponding activation energies of electropolymerization were calculated to be 0.9, 0.9, and 0.8 kJ/mole. The molecular weights of poly(o-TMS-phenol) and poly(m-TMS-phenol) were determined by gel permeation chromotography. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1121–1126, 1997     

Quinone propionic acid‐based redox‐triggered polymer nanoparticles for drug delivery: Computational analysis and in vitro evaluation

Redox‐responsive polymers with pendant quinone propionic acid groups as a redox trigger were optimized by computational modeling to prepare efficient redox‐triggered polymer nanoparticles (NPs) for drug delivery. Lipophilicities at complete reduction of redox‐responsive polymers (<5000 Da) constructed with adipic acid and glutaric acid were remarkably reduced to range from ?6.29 to ?0.39 compared with nonreduced state (18.87–32.46), suggesting substantial polymer solubility reversal in water. Based on this hypothesis, redox‐responsive NPs were prepared from the synthesized polymers with paclitaxel as model cancer drug. The average size of paclitaxel‐loaded NPs was 249.8 nm and their reconstitutions were stable over eight weeks. In vitro drug release profiles demonstrated the NPs to release >80% of paclitaxel over 24 h at a simulated redox‐state compared with 26.5 to 41.2% release from the control. Cell viability studies revealed that the polymer was nontoxic and the NPs could release paclitaxel to suppress breast cancer cell growth. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40461.     

Interaction of molecularly imprinted polymers with creatinine

Memory sites toward clinically relevant creatinine have been imparted in polymers based on methacrylic acid, N-vinyl pyrrolidine, and 2-hydroxy ethyl methacrylate by the technique of molecular imprinting. The polymers are subjected to interaction with creatinine and creatine, a molecule of close resemblance with creatinine. The results show that selectivity is largely governed by the nature of the monomer. The reusability of the polymer is also demonstrated. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2539–2542, 1997     

Synthesis and characterization of wholly aromatic polyamides containing pendent amino and cyano groups

The new pyrazole-ring containing diamine monomer with amino and cyano groups, 1,3-di-p-aminophenyl-4-cyano-5-aminopyrazole (PYA), was prepared from 4-nitrobenzoyl chloride and 4-nitrophenyl hydrazine with 4 steps. The monomer was converted to polyamides with terephthaloyl chloride and isophthaloyl chloride. The amino and cyano groups on the pyrazole-ring were not affected during polymerization. The synthesized polyamides having intrinsic viscosities of 0.92 – 1.18 dL/g were amorphous, and soluble in polar aprotic solvents and boiling acetone and THF. The polymers had high glass transition temperatures and high thermal stability. 5% weight loss temperatures in nitrogen occurred around 490 °C, but these polymers are partially degraded at 300 °C in air due to the amino group on the pyrazole-ring. Received: 6 March 1997/Accepted: 1 April 1997