Synthesis and properties of photoluminescent copolymer containing 1,3,4‐oxadiazole and carbazole rings

The luminescent copolymer 2‐phenyl‐5‐[3′‐(methacrylamido)phenyl]‐1,3,4‐oxadiazole and vinylcarbazole (PMAPO–VCZ), combining hole‐facilitating moiety, carbazole ring, and electron‐facilitating moiety, 1,3,4‐oxadiazole, as side groups, was synthesized by a radical polymerization of the olefinic monomer PMAPO and VCZ. For comparison, the homopolymer P‐PMAPO was also synthesized by similar procedures. The solubility, thermal, and optical properties of the copolymers were investigated. The synthesized copolymer was soluble in common organic solvents but the homopolymer of PMAPO was dissolved only by hot THF. Thermogravimetric analysis and differential scanning calorimetry measurements showed that the copolymer and homopolymer exhibit good thermal stability up to 360 and 340°C with glass‐transition temperatures higher than 105 and 65°C, respectively. The photoluminescence properties were investigated. The results showed that the copolymer emits blue and blue‐green light and the emission spectra of monomer and polymers exhibit obvious solvent effect. With the increase of polarity of solvents, the fluorescence spectra distinctly change, appearing with a red shift at room temperature. The concentration‐dependent emission spectra change significantly with the increase of concentration. In addition, when N,N‐dimethylaniline (DMA) was gradually added to the solution of copolymers, the emission intensity of fluorescence was dramatically increased. However, when the concentration of DMA was increased beyond a certain level, the emission intensity of fluorescence gradually decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2777–2783, 2004     

Synthesis and fluorescence in solution of polybenzimidazolylphenylenephthalamides

Six polybenzimidazolylphenylenephthalamides (PBIPPA), two meta/para isomers, and four meta/para isomers that had different distances between a benzimidazolyl and the adjacent benzimidazolyl in a polymer chain were synthesized. They were soluble in N,N‐dimethylacetamide. In addition to the fluorescence from the π → π* transition of isolated phenylbenzimidazole, a fluorescence from a chromophore complex in the grand state appeared in the fluorescence spectra, which was observed at higher concentrations. The concentration dependence of the intensity of the fluorescence was investigated in order to learn whether the chromophore complex was intermolecular or intramolecular. It was concluded that the chromophore complex is intramolecular, a conclusion supported by the viscometric results. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1412–1416, 2003     

From a laboratory to a pilot scale production of natural rubber grafted with PMMA

Graft copolymers of natural rubber and poly (methyl methacrylate) (NR‐g‐PMMA) were prepared in a laboratory scale, and then extended to a pilot scale production. Reaction conditions were first assessed based on a preparation in the laboratory scale with a reactor capacity of 1.5 l. An optimum grafting efficiency was obtained when cumene hydroperoxide/tetraethylenepentamine (CHP/TEPA) redox initiator was used at the reaction temperature and time of 50°C and 3 h, respectively. MMA monomer was used without purification in the polymerization process comparing with the purified one by means of extraction. It was found that only a slight decrease of grafting efficiency was observed when the nonpurified monomer was used in the reaction. The nonpurified monomer was therefore used to prepare the NR‐g‐PMMA in a pilot scale production with a reactor capacity of 260 L. Various weight ratios of NR/MMA at 50/50, 60/40, 70/30, and 85/15 were studied. The resulting graft copolymers were characterized by FTIR and ¹H‐NMR techniques. It was found that increasing concentration of MMA caused an increase of free PMMA (i.e., homopolymer) but a decrease of free NR (i.e., ungrafted NR) and grafting efficiency. Quantity of grafted PMMA on the NR backbone was estimated using the integrated peak areas of ¹H‐NMR spectra and quantitative analysis by extraction method. The results were found to be in good agreement. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of methyl methacrylate on the properties of transparent flame retardant unsaturated phosphate ester copolymer

The effect of methyl methacrylate (MMA) on the properties of transparent flame retardant unsaturated phosphate ester copolymer (poly[UPE‐co‐MMA]) prepared by bulk polymerization technique was investigated. Fourier transform infrared spectra, gel fraction (G) test, and dynamic mechanical analysis revealed the structure and crosslinking density of poly(UPE‐co‐MMA) copolymers. The thermal degradation and flame retardancy of copolymers were indicated by thermogravimetric analysis, limiting oxygen index (LOI), and microscale combustion calorimeter (MCC) test. Besides, the mechanical properties and transparency were tested with testing machines and solid ultraviolet absorption spectra. As the MMA content increased to 50%, the copolymer contained 50 wt% MMA showed the maximal G (88.93%) and transmittance was up to 91.72%. From the poly(UPE‐co‐MMA) copolymers, the tensile strength increased from 14.62 to 26.95 MPa, assigned to the increase of crosslinking density of copolymers. The char yield of poly(UPE‐co‐MMA) was up to 21.18 wt%, which was a result of decomposition of phosphate groups, producing a phosphorus‐rich layer that increased the thermal stability of the residues. LOI and MCC results confirm that the introduction of MMA can retain the flame retardancy of copolymer remarkably. POLYM. ENG. SCI., 59:2103–2109, 2019. © 2019 Society of Plastics Engineers     

Photocrosslinkable copolymers based on 4‐acryloyloxyphenyl‐3′‐chlorostyryl ketone and methyl methacrylate: synthesis,comonomer reactivity ratios and UV photosensitivity

A new photosensitive acrylate monomer having a pendant chlorocinnamoyl moiety (APCSK) was copolymerized with methyl methacrylate (MMA) in different feed compositions in ethyl acetate solution at 70°C using benzoyl peroxide as a free‐radical initiator. The newly synthesized copolymers were characterized by FTIR, ¹H and ¹³C nuclear magnetic resonance (NMR) spectral techniques, as well as by size‐exclusion chromatography. Their thermal behaviour was assessed by thermogravimetric analysis in air and differential scanning calorimetry under nitrogen atmosphere. The copolymers exhibit no phase separation since there is only one glass transition temperature (T_g) value in the region of copolymer composition studied. The reactivity ratios of the comonomers were calculated by adopting linearization methods such as the Fineman–Ross (F‐R), Kelen–Tudos (K‐T) and extended Kelen–Tudos (ExtK‐T) methods, and by a non‐linear error‐in‐variables model method (EVM) using a computer program (RREVM). The results suggest that MMA is more reactive than APCSK and that their copolymerization leads to the formation of random copolymers. The photosensitivity of the copolymer samples was studied in solution as well as in thin films through UV irradiation. The influence of different factors, including solvent nature, concentration, temperature, photosensitizer and copolymer composition, on the rate of photocrosslinking of the photoreactive copolymers was investigated for effective industrial application of these polymers as negative photoresists. Copyright © 2004 Society of Chemical Industry     

Studies on the microstructure of vinyl/N‐phenylmaleimide copolymers by NMR and their applications

The micro‐ and stereostructures and sequence distribution of methyl methacrylate (MMA)/N‐phenylmaleimide (PMI) and styrene (St)–PMI copolymers were studied in detail with NMR spectroscopy. The MMA–PMI copolymer was in a random sequence distribution and the St–PMI copolymer was alternating in structure. Some micro‐ and stereoinformation of the MMA–PMI copolymers could be obtained from ¹H‐NMR spectra. The average number sequence length obtained from the copolymer triad by ¹³C‐NMR spectra was in agreement with that calculated from the reactivity ratios measured by an elemental analyzer. From the triad fraction of the copolymer measured by ¹³C‐NMR, the copolymer chain of MMA–PMI was proved to be a one‐order Markov chain. More suitable propagation reactions were proposed from the deviation of sequence distribution of the St–PMI copolymer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2581–2587, 2000     

Studies on blends of LLDPE and polar polymers compatibilized by a random copolymer

Compatibilization of blends of linear low‐density polyethylene (LLDPE)–poly(methyl methacrylate) (PMMA) and LLDPE–copolymer of methyl methacrylate (MMA) and 4‐vinylpyridine (poly(MMA‐co‐4VP) with poly(ethylene‐co‐methacrylic acid) (EMAA) have been studied. Mechanical properties of the LLDPE–PMMA blends increase upon addition of EMAA. In order to further improve interfacial adhesion of LLDPE and PMMA, 4‐vinyl pyridine units are introduced into PMMA chains, or poly(MMA‐co‐4VP) is used as the polar polymer. In LLDPE–poly(MMA‐co‐4VP)–EMAA blends, interaction of MAA in EMAA with 4VP of poly(MMA‐co‐4VP) causes a band shift in the infrared (IR) spectra. Chemical shifts of N_1s binding energy in X‐ray photoelectronic spectroscopy (XPS) experiments indicate a transfer of proton from MAA to 4VP. Scanning electron microscopy (SEM) pictures show that the morphology of the blends were improved upon addition of EMAA. Nonradiative energy transfer (NRET) fluorescence results attest that there exists interdiffusion of chromophore‐labeled LLDPE chains and chromophore‐labeled poly(MMA‐co‐4VP) chains in the interface. Based on experimental results, the mechanism of compatibilization is studied in detail. Compatibilization is realized through the interaction between MAA in EMAA with 4VP in poly(MMA‐co‐4VP). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 967–973, 1999     

The synthesis of PHA‐g‐(PTHF‐b‐PMMA) multiblock/graft copolymers by combination of cationic and radical polymerization

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3‐hydroxy alkanoate)‐g‐(poly(tetrahydrofuran)‐b‐poly(methyl methacrylate)) (PHA‐g‐(PTHF‐b‐PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA‐g‐PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHx) in the presence of AgSbF₆. Therefore, PHA‐g‐PTHF graft copolymers with hydroxyl ends were produced. In the presence of Ce⁺⁴ salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA‐g‐(PTHF‐b‐PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their γ‐values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using ¹H‐NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of oil sorbers based on docosanyl acrylate and methacrylates copolymers

Docosanyl acrylate (DCA) monomer was copolymerized with different monomer feed ratios of cinnamoyloxy ethyl methacrylate (CEMA) or methyl methacrylate (MMA) monomer to produce different compositions for DCA/CEMA or DCA/MMA copolymer with low conversions.¹H NMR spectroscopy was used to confirm the copolymer structure. DCA was crosslinked with different mol % of CEMA or MMA using dibenzoyl peroxide as initiator and various weight percentages of either 1,1,1‐trimethylolpropane triacrylates or 1,1,1‐trimethylolpropane trimethacrylates crosslinkers. The effects of monomer feed composition, crosslinker concentration, and the hydrophobicity of the copolymer units on swelling properties of the crosslinked polymers were studied through the oil absorbency tests. The network parameters, such as polymer solvent interaction (χ), effective crosslink density (υ_e), equilibrium modulus of elasticity (G_T), and average molecular weight between crosslinks (M_c), were determined and correlated with the structure of the synthesized copolymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of copolymers with the same proportions of polystyrene and poly(ethylene oxide) compositions but different connection sequence by the efficient Williamson reaction

The AB type diblock PS‐b‐PEO and ABA type triblock PS‐b‐PEO‐b‐PS copolymers containing the same proportions of polystyrene (PS) and poly(ethylene oxide) (PEO) but different connection sequence were synthesized and investigated. Using the sequential living anionic polymerization and ring‐opening polymerization mechanisms, diblock PS‐b‐PEO copolymers with one hydroxyl group at the PEO end were obtained. Then, using the classic and efficient Williamson reaction (realized in a ‘click’ style), triblock PS‐b‐PEO‐b‐PS copolymers were achieved by a coupling reaction between hydroxyl groups at the PEO end of PS‐b‐PEO. The PS‐b‐PEO and PS‐b‐PEO‐b‐PS copolymers were well characterized by ¹H NMR spectra and SEC measurements. The critical micelle concentration (CMC) and thermal behaviors were also investigated by steady‐state fluorescence spectra and DSC, respectively. The results showed that, because the PEO segment in triblock PS‐b‐PEO‐b‐PS was more restricted than that in diblock PS‐b‐PEO copolymer, the former PS‐b‐PEO‐b‐PS copolymer always gave higher CMC values and lower crystallization temperature (T_c), melting temperature (T_m) and degree of crystallinity (X_c) parameters. © 2015 Society of Chemical Industry     

Thermal analysis,glass transition temperature and rheological behaviour of emulsion copolymers of methyl methacrylate with styrene

Poly(MMA‐ran‐St) samples were synthesized under monomer‐starved conditions (drop feeding method) by emulsion copolymerization. Their thermostability was determined by thermogravimetric analysis. The glass transition temperature (T_g) of the copolymers was determined by differential scanning calorimetry (DSC) and torsional braid analysis (TBA). The results showed that the MMA–St copolymers exhibit an asymmetric T_g versus composition curve, which could not be interpreted by Johnston's equation, taking the different contributions of the diads to the T_g of the copolymer into consideration. A new sequence distribution equation taking into account the different contributions of the triads was proposed to predict the copolymer T_g. The new equation fitted the experimental data exactly. The T_g determined by torsional braid analysis (TBA) is higher than the one determined by DSC, but the difference is not constant. The rheological behaviour of the copolymers was also studied and T_gTBA‐T_gDSC increased with the increasing flow index of the copolymer. © 2003 Society of Chemical Industry     

稀土配合物及其共聚物的合成与性能研究

以丙烯酸(HAA)、甲基丙烯酸(HMA)及1,10-邻菲罗啉(Phen)为配体与氧化铕(Eu2O3)反应得到二元配合物Eu(AA)3、Eu(MA)3和三元配合物Eu(AA)3Phen、Eu(MA)3Phen。将生成的配合物与HMA和甲基丙烯酸甲酯(MMA)共聚,得到一系列三元共聚物。通过元素分析、红外光谱、荧光光谱和热分析对配合物进行了分析与表征,发现配合物具有良好的荧光强度和热稳定性。三元配合物的荧光强度相对于二元配合物有显著提高。共聚物可发射Eu3+的特征荧光,荧光强度随配合物含量的增加而增加,且未发生浓度猝灭现象。三元配合物在反应单体MMA和HMA中的溶解度低于二元配合物,从而使在最大溶解度下二元配合物与反应单体生成共聚物的荧光强度高于相应的三元配合物与反应单体生成的共聚物。     

Effect of methyl methacrylate content on coatings’ properties of palm oleic acid-based macromer

The macromer was synthesized using medium oil length oleic acid, phthalic anhydride, and glycerol. The synthesized macromer and methyl methacrylate (MMA) were copolymerized by free radical polymerization in toluene. The ratio between the macromer and MMA changed, and the effects on different properties of the copolymers, such as glass transition temperature (T _g) and film properties, were studied. The macromer and copolymer structures were characterized by FTIR and ¹H NMR spectroscopies. The coatings prepared with the highest ratio of MMA exhibited better overall physico-chemical properties. Alternatively, Tafel polarization curves showed that the corrosion rate value in NaCl solution decreases significantly when the MMA content is increased. Dynamic mechanical analysis results revealed that the increasing amounts of MMA lead to increasing T _g values of copolymers.     

Degradation kinetics of poly(HDDA‐co‐MMA)

1,6‐hexanediol diacrylate (HDDA) and methyl methacrylate (MMA) were copolymerized in different weight ratios using UV light induced photo‐polymerization to give poly(HDDA‐co‐MMA). Differential scanning calorimetry shows that copolymer was formed. The thermogravimetric and differential scanning calorimetric studies with different heating rates were carried out on these copolymers to understand the nature of degradation and to determine its kinetics. Different kinetic models were adopted to evaluate various parameters like the activation energy, the order, and the frequency factor. These analyses are important to study the binder removal from 3D‐shaped ceramic objects made by techniques like Solid free form fabrication. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanostructuration of Unsaturated Polyester by All‐Acrylic Block Copolymers, 1 ‐ Use of High‐Molecular‐Weight Block Copolymers

Nanostructuration of maleate and orthophthalic unsaturated polyester (UP) resins was achieved by the use of high molecular weight amphiphilic PBA‐b‐P(MMA‐co‐DMA)₂ triblock copolymers. PBA is fully immiscible in cured UP resins, and the miscibility of P(MMA‐co‐DMA) random copolymers can be ensured with a minimum DMA content of 12 mol‐%. When using the triblock copolymers, fully transparent and nanostructured thermosets are obtained with a minimum DMA content in the outer blocks; the value of which is higher than 12 mol‐% and depends on the UP chemical structure. Finally, the fracture toughness of nanostructured thermoset was evaluated: for a triblock copolymer content as low as 5 wt.‐%, a 50% increase of K_Ic was obtained, as compared to the neat thermoset.

     

Toluene‐vapor sorption of chemically modified methyl methacrylate‐co‐chloromethyl styrene copolymers with N,N,‐dimethyl‐1,3‐propanediamine measured with a quartz crystal microbalance

The sorption properties of toluene vapor were measured for methyl methacrylate (MMA)‐co‐chloromethyl styrene (CMSt) copolymers chemically modified with N,N‐dimethyl‐1,3‐propanediamine (DMPDA) to develop a novel quartz crystal microbalance toluene‐vapor sensor coating. The influence of the structure of the comonomer, the composition of the copolymer, and the film thickness on the toluene sorption properties were investigated. The modified MMA–CMSt copolymers were capable of large, fast, and reversible sorption versus the modified styrene–CMSt copolymers. The largest sorption capacity was obtained for MMA–CMSt–DMPDA with a 96 mol % CMSt concentration. These behaviors were explained by a combination of the plasticization of the copolymers by the introduction of bulky DMPDA at lower CMSt concentrations and the formation of a loosely crosslinked structure at higher CMSt concentrations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Copolymers of methyl methacrylate and acrylate comonomers: Synthesis and characterization

Methyl methacrylate (MMA) has been copolymerized with n-butyl acrylate (n-BA), ethyl acrylate (EA), and 2-ethylhexyl acrylate (2-EHA) in solution at 70°C using benzoyl peroxide as free radical initiator. The copolymer composition was estimated by the ¹H-NMR spectroscopic technique. The copolymers were further characterized by IR, XRD, TGA, DTA, DSC, GPC, and solubility. The adhesive characteristics of the copolymers to cellulosic substrate are also reported. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of novel rod–coil diblock copolymers of poly(methyl methacrylate) and liquid crystalline segments of poly(2,5‐bis[(4‐methoxyphenyl)oxycarbonyl] styrene)

Liquid crystalline diblock copolymers with different molecular weights and low polydispersities were synthesized by atom transfer radical polymerization of methyl methacrylate (MMA) and 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene (MPCS) monomers. The block architecture (coil‐conformation of MMA segment and rigid‐rod of MPCS segment) of the copolymer was experimentally confirmed by a combination of ¹H nuclear magnetic resonance and gel permeation chromatograph techniques. The liquid crystalline behaviour of the copolymer was studied using differential scanning calorimetry and polarized optical microscope. It was found that the liquid crystalline behaviour was dependent on the number average molecular weight of the rigid segment. Only those copolymers with M_n(GPC) of the rigid block above 9200 g mol^?1 could form liquid crystalline phases higher than the glass transition temperature of the rigid block. The random copolymers MPCS‐co‐MMA were also synthesized by conventional free radical polymerization. The molar content of MPCS in MPCS‐co‐MMA had to be higher than 71% to maintain liquid crystalline behaviour. © 2003 Society of Chemical Industry     

Synthesis of well‐defined comb‐like amphiphilic copolymers with protonizable units in the pendent chains: 1. Preparation of narrow polydispersity copolymers of methyl methacrylate and 2‐hydroxyethyl methacrylate by atom‐transfer radical polymerization

Well‐defined methyl methacrylate (MMA) and 2‐(trimethylsiloxy)ethyl methacrylate (Pro‐HEMA) copolymers were prepared by atom‐transfer radical polymerization(ATRP), using CuCl/2,2′‐bipyridine as catalytic system and p‐toluenesulfonyl chloride as initiator. ATRP process of MMA and Pro‐HEMA was monitored by ¹H NMR, and the kinetic curves of the MMA/Pro‐HEMA copolymerization were plotted in terms of the ¹H NMR data. At low content of Pro‐HEMA in the feed composition, the copolymerization can be well controlled with the molecular weight, polydispersity and the monomer distribution in the copolymer chain. With the increase of Pro‐HEMA content in the feed mixture, the composition of the final copolymer deviates from the composition of the feed mixture gradually, and gradient copolymers of MMA/Pro‐HEMA can be obtained. Through the hydrolysis process, well‐defined copolymers of MMA/HEMA were obtained from poly(MMA/Pro‐HEMA). Copyright © 2003 Society of Chemical Industry     

Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF₆ and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with M_w varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, ¹H‐NMR, and ¹³C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004