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1.
Cationic ring‐opening copolymerization behavior of 1,5,7,11‐tetraoxaspiro[5.5]undecane (SOC1) and ε‐caprolactone (CL), and the thermal behavior of the obtained copolymers are described. When SOC1 and CL were cationically copolymerized under various feed ratios using BF3OEt2 as the initiator in CH2Cl2 at 25 °C, the corresponding copolymers were obtained in 77–99% yields. The 1H NMR spectroscopic analysis of the copolymers revealed that the copolymer compositions were almost identical to the feed ratios, and the diad ratios of SOC1–SOC1/SOC1–CL and CL–SOC1/CL–CL are 48.0/52.0 and 54.3/45.7. These observations proved the random structures of the copolymers without containing the long blocks of the homopolymer sequences. Differential scanning calorimetric (DSC) analysis revealed that the melting points and melting entharpies decreased with the increase of the SOC1 unit compositions, suggesting that the copolymers gain flexibility as the SOC1 unit increases. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2937–2942, 2006  相似文献   

2.
A series of copolymers composed of two monomer units having a polar phosphorylcholine group and an apolar fluorocarbon group with a controlled monomer unit sequence were synthesized by a reversible addition‐fragmentation chain transfer (RAFT) living radical polymerization method. 2‐Methacryloyloxyethyl phosphorylcholine (MPC) and 2,2,2‐trifluoroethyl methacrylate (TFEMA) were selected as the monomers, because they have disparate polarity. Furthermore, to investigate the influence of the monomer unit sequence in a polymer chain on the phase‐separated structure in the bulk and surface structure, copolymers having a continuous change in the monomer unit composition along the polymer chain (gradient copolymer) were synthesized, as well as random and block copolymers. The analysis of instantaneous composition revealed a continuous change in the monomer unit composition in the gradient copolymer and the statistical monomer unit sequence in the random copolymer. Thermal analysis assumed that the gradient sequence of the monomer unit would make the phase‐separated structure in the bulk ambiguous, while the well‐defined and monodispersive block sequence would undergo the distinct phase‐separation due to the extreme difference in the polarity of the component monomer units. The preliminary surface characterization of the synthesized polymers indicated the monomer unit sequence in the polymer chain would much influence on the surface structure. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6073–6083, 2005  相似文献   

3.
The copolymers of 2‐methoxy‐5‐2′‐ethyl‐hexyloxy‐1,4‐phenylenevinylene (MEH‐PV) and 2,3‐diphenyl‐5‐octyl‐1,4‐phenylenevinylene were prepared via the Gilch route with their chain compositions and the reactivity ratios of the monomers estimated by 1H NMR spectroscopy. The results indicated that the copolymers tended to form an alternative copolymer as the feed ratio of the monomers closed to one‐half. When an individual copolymer solution in tetrahydrofuran was spun‐cast to form a film, the MEH‐PV units were able to attract the like units from the adjacent chains. As a result, the ultraviolet–visible absorption spectrum of the alternative copolymer in film form was broader than the spectra of those with different compositions. The photoluminescence spectra of the copolymers in film form exhibited the characteristic shoulder of poly(2‐methoxy‐5‐2′‐ethyl‐hexyloxy‐1,4‐phenylenevinylene), even though the content of MEH‐PV units was not great enough for the formation of repeat units in sequence. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2180–2186, 2003  相似文献   

4.
The free‐radical copolymerization of N‐phenylmaleimide (N‐PhMI) with acrylic acid was studied in the range of 25–75 mol % in the feed. The interactions of these copolymers with Cu(II) and Co(II) ions were investigated as a function of the pH and copolymer composition by the use of the ultrafiltration technique. The maximum retention capacity of the copolymers for Co(II) and Cu(II) ions varied from 200 to 250 mg/g and from 210 to 300 mg/g, respectively. The copolymers and polymer–metal complexes of divalent transition‐metal ions were characterized by elemental analysis, Fourier transform infrared, 1H NMR spectroscopy, and cyclic voltammetry. The thermal behavior was investigated with differential scanning calorimetry (DSC) and thermogravimetry (TG). The TG and DSC measurements showed an increase in the glass‐transition temperature (Tg) and the thermal stability with an increase in the N‐PhMI concentration in the copolymers. Tg of poly(N‐PhMI‐co‐AA) with copolymer composition 46.5:53.5 mol % was found at 251 °C, and it decreased when the complexes of Co(II) and Cu(II) at pHs 3–7 were formed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4933–4941, 2005  相似文献   

5.
This article extends the composition of linear low‐density polyethylene (LLDPE) resins to that containing 1‐decene comonomer units, and examines the effects of comonomer (type and concentration) to copolymerization and physical properties of LLDPE resins. CGC metallocene technology, under high temperature and high pressure (industrial reaction condition), was used to prepare three types of well‐defined LLDPE copolymers containing 1‐hexene, 1‐octene, and 1‐decene units. They show high molecular weight with narrow molecular weight and composition distributions, comparative catalyst activities, and similar comonomer effects. However, 1‐decene seems to exhibit significantly higher comonomer incorporation than 1‐hexene and 1‐octene, which may be associated with its high boiling point, maintaining liquid phase during the polymerization. The resulting LLDPE copolymers show a clear structure–property relationship. Melting temperature and crystallinity of the copolymer are governed by mole % of comonomer. The increase of branch density linearly decreases the LLDPE melting point and exponential reduction of its crystallinity. On the other hand, the density of the copolymer decreases with the increase of comonomer weight %, which shows a sharp linear relationship in the low comonomer content. The tensile properties of 1‐decene‐based LLDPE are very comparative with those of the commercial LLDPE resins with similar compositions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 639–649, 2007  相似文献   

6.
Radical copolymerization of alkyl 2‐norbornene‐2‐carboxylates (alkyl = Me 1a , nBu 1b ) with alkyl acrylates (alkyl = ethyl, methyl, and n‐butyl) was investigated. Copolymerization of 1a,b with the alkyl acrylates initiated by 1,1′‐azobis (cyclohexane‐1‐carbonitrile) at 85 °C proceeded to give random copolymers, although the homopolymerization of 1a,b did not proceed efficiently under the same conditions. Typically, bulk copolymerization of 1a with ethyl acrylate in a feed ratio of 1:3 ([ 1a ]:[EA]) afforded a copolymer with Mn = 33,300 containing 19.4 mol % of 1a unit in the composition. An increase of Tg derived from the incorporation of the rigid norbornane framework was observed, although the extent of the temperature rise was rather moderate. The ternary radical copolymerization of 1a,b /alkyl acrylate/N‐phenylmaleimide proceeded to give copolymers with the three repeating units in the main chain. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4597–4605, 2007  相似文献   

7.
It was demonstrated that a series of copolymers consisting of 1,4‐phenylenevinylene (PV) and 1,4‐phenylene‐1,2‐ethanediyl (PE) units could be prepared from a single monomer, p‐(methoxymethyl)benzyl chloride, via the chemical vapor deposition polymerization (CVDP) method. The composition of the copolymers could be varied simply by altering the monomer activation temperature. The higher the temperature, the lower the content of the PV unit. The photo (PL)‐ and electroluminescence (EL) properties of the copolymers that revealed a blueshift when compared with PPV strongly depend on the amount of the PE units incorporated. The external quantum efficiencies of the electroluminescence devices having the configuration of ITO/PEDOT‐PSS/copolymer/Al‐Li were higher than that of PPV, which can be ascribed to the improved confinement of excitons. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 742–751, 2005  相似文献   

8.
Copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and methyl acrylate (MA) containing ester units both in the backbone and as pendant groups were synthesized by free‐radical copolymerization. The influence of reaction conditions such as the polymerization time, temperature, initiator concentration, and comonomer feed ratio on the yield, molecular weight, and copolymer composition was investigated. The structure of the copolymers was confirmed by 1H NMR, 13C NMR, and IR spectroscopy. Differential scanning calorimetry indicated that the copolymers had a random structure. An NMR study showed that hydrogen transfer occurred during the copolymerization. The reactivity ratios of the comonomers were rMDO = 0.0235 and rMA = 26.535. The enzymatic degradation of the copolymers obtained was carried out in the presence of proteinase K or a crude enzyme extracted from earthworms. The experimental results showed that the higher ester molar percentage in the backbone caused a faster degradation rate. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2898–2904, 2003  相似文献   

9.
A series of hole and electron transporting random and block copolymers consisting of triphenylamine moiety as a hole transporting unit and oxadiazole moiety as an electron transporting unit have been prepared via a nitroxide mediated radical polymerization. Oxadiazole monomers with t‐butyl or trifluoromethyl groups, 2 and 7, respectively, were used for copolymerization. Photoluminescent measurements of polymers revealed that the formation of the exciplex between triphenylamine and oxadiazole units tends to occur in the order of random copolymers, block copolymers, and polymer blends, implying phase‐separated morphologies in block or blend systems. The polymers were applied for OLED devices, and we found that the morphology in the polymer layer critically affected device performance. The block copolymer comprising hole and electron transporting units with the composition of 14/86 showed the highest external quantum efficiency over 10%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1461–1468, 2010  相似文献   

10.
The solution properties of random and block copolymers based on 2‐ethyl‐2‐oxazoline (EtOx) and 2‐nonyl‐2‐oxazoline (NonOx) were investigated in binary solvent mixtures ranging from pure water to pure ethanol. The solubility phase diagrams for the random and block copolymers revealed solubility (after heating), insolubility, dispersions, micellization as well as lower critical solution temperature (LCST) and upper critical solution temperature behavior. The random and block copolymers containing over 60 mol % pNonOx were found to be solubilized in ethanol upon heating, whereas the dissolution temperature of the block copolymers was found to be much higher than for the random copolymers due to the higher extent of crystallinity. Furthermore, the block copolymer containing 10 mol % pNonOx exhibited a LCST in aqueous solution at 68.7 °C, whereas the LCST for the random copolymer was found to be only 20.8 °C based on the formation of hydrophobic microdomains in the block copolymer. The random copolymer displayed a small increase in LCST up to a solvent mixture of 9 wt % EtOH, whereas further increase of ethanol led to a decrease in LCST, which is probably due to the “water‐breaking” effect causing an increased attraction between ethanol and the hydrophobic part of the copolymer. In addition, the EtOx‐NonOx block copolymers revealed the formation of micelles and dynamic light scattering demonstrated that the micellar size is increasing with increasing the ethanol content due to the enhanced solubility of EtOx. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 515–522, 2009  相似文献   

11.
Crystal‐packing, optical, and electrical properties of poly(2,5‐dihydroxy‐1,4‐phenylene benzobisthiazole) (DiOH‐PBZT) and copolymers of DiOH‐PBZT/poly(1,4‐phenylene‐benzobisthiazole) (PBZT) were examined. Intramolecular hydrogen bonds between the hydroxyl units and the neighboring nitrogen atoms, as evidenced by the IR spectra, led to the formation of a pseudoladder chain structure and changed the chain packing. The (200) and (010) planes were both affected by the copolymer composition, with the (200) plane spacing increasing from 5.895 to 6.482 Å and the (010) plane spacing decreasing from 3.539 to 3.404 Å with the transition from the unsubstituted PBZT homopolymer to the DiOH‐PBZT homopolymer. The cell dimensions of the copolymers were simple averages of those of the individual homopolymers, suggesting the isomorphic crystal structure formation of the two units. The c‐axis spacing, however, remained unchanged. The increase in the conjugation length of the copolymers as the dihydroxy content increased was confirmed by the bathochromic shift of the absorption band in the ultraviolet–visible spectra. The intrinsic conductivities of the copolymers were 3 orders of magnitude higher than that of the unsubstituted PBZT. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 559–565, 2001  相似文献   

12.
A series of fluorene‐based copolymers containing hole blocking/electron transporting diphenyloxadiazole units were synthesized by means of Suzuki‐Miyaura coupling of selected aromatic dibromo‐ and diboronato‐ derivatives catalyzed with a Pd(PPh3)4 catalyst. All of the copolymers with various composition of main‐chain units were characterized by SEC chromatography, NMR, UV–vis, fluorescence and IR spectroscopy, and DSC. The emission stability of fluorene copolymers was improved by the replacement of alkyl groups on the C‐9 carbon of fluorene with aryl groups or by the incorporation of anthracene units into the copolymer main chain. A comparison of luminescence properties of pristine and annealed thin layers of studied copolymers was performed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4532–4546, 2009  相似文献   

13.
This study applied the macromonomers and glycidyl methacrylate (GMA) to synthesize a series of the graft copolymers, poly(GMA)‐graft‐poly(Z‐L ‐lysine), and investigated the conformation of the graft copolymer. The graft copolymers were synthesized with different GMA monomer ratios (28 to 89%) and different degrees of polymerization (DP) (8 to 15) of the poly(Z‐L ‐lysine) side chain to analyze secondary structure relationships. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and both wide angle and small angle X‐ray scattering spectroscopy (WAXS, SAXS) were used to investigate the relationship between the microstructure and conformation of the graft copolymers and the different monomer ratios and side chain DP. In AFM images, n8‐G89 (the graft copolymer containing 89% GMA units and the macromonomer DP is 8) showed tiny and uniform rod‐like structures, and n14‐G43 (the graft copolymer containing 43% GMA units and the macromonomer DP is 14) showed uniform rod‐like structures. FTIR spectra of the graft copolymers showed that the variations of α‐helix and β‐sheet secondary structures in the graft copolymers relate to the monomer ratios of the graft copolymers. However, the X‐ray scattering patterns indicated that the graft copolymer conformations were mainly dependent on the poly(Z‐L ‐lysine) side chain length, and these results were completely in accordance with the AFM images. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4655–4669, 2009  相似文献   

14.
The synthesis and characterization of copolymers containing 2‐ethylhexyl methacrylate and a quadruple‐hydrogen‐bonding site, 2‐ureido‐4[1H]‐pyrimidone methacrylate (UPyMA), are described. An analogous dimeric hydrogen‐bond‐containing copolymer based on 2‐ethylhexyl methacrylate and methacrylic acid (PEHMA‐co‐MAA) was also synthesized for comparative purposes. The glass‐transition temperatures of the poly(2‐ethylhexyl methacrylate‐co‐2‐ureido‐4[1H]‐pyrimidone methacrylate) (PEHMA‐co‐UPyMA) series increased linearly with increasing UPyMA content. Creep compliance measurements as a function of temperature indicated a decrease in the creep compliance with increasing UPyMA content over the range of 1–10 mol % UPyMA. Melt rheological analysis also showed an increase and lengthening of the plateau modulus as a function of frequency with increasing UPyMA content, as well as increasing complex viscosity as a function of temperature. The analogous PEHMA‐co‐MAA copolymer, which contained 11 mol % methacrylic acid, showed, in the melt rheological analysis, behavior similar to that of the PEHMA‐co‐UPyMA copolymer containing only 1 mol % UPyMA units. The multiple‐hydrogen‐bond‐containing copolymers were successfully analyzed with time–temperature superposition for the construction of master curves. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4618–4631, 2005  相似文献   

15.
A series of random copolymers of N‐isopropylacrylamide (NIPAM) and sodium 2‐acrylamido‐2‐methyl‐1‐propanesulphonate (AMPS) was synthesized by free‐radical copolymerization. The content of AMPS in the copolymers ranged from 1.1 to 9.6 mol %. The lower critical‐solution temperature (LCST) of copolymers in water increased strongly with an increasing content of AMPS. The influence of polymer concentration on the LCST of the copolymers was studied. For the copolymers with a higher AMPS content, the LCST decreased faster with an increasing concentration than for copolymers with a low content of AMPS. For a copolymer containing 1.1 mol % of AMPS the LCST dropped by about 3 °C when the concentration increased from 1 to 10 g/L, whereas for a copolymer containing 9.6 mol % of AMPS the LCST dropped by about 10 °C in the concentration range from 2 to 10 g/L. It was observed that the ionic strength of the aqueous polymer solution very strongly influences the LCST. This effect was most visible for the copolymer with the highest content of AMPS (9.6 mol %) for which an increase in the ionic strength from 0.2 to 2.0 resulted in a decrease in the LCST by about 27 °C (from 55 to 28 °C), whereas for the copolymer containing 1.1 mol % of AMPS the LCST decreased only by about 6 °C (from 37 to 31 °C) when the ionic strength increased from 0.005 to 0.3. The reactivity ratios for the AMPS and NIPAM monomer pairs were determined using different methods. The values of rAMPS and rNIPAM obtained were 11.0–11.6 and 2.1–2.4, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2784–2792, 2001  相似文献   

16.
Copolymers of monomers 2,4‐dichlorophenyl methacrylate (2,4‐DMA) and methyl methacrylate (MMA) were synthesized with different monomer feed ratios using toluene as a solvent and 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70 °C. The copolymers were characterized by IR‐spectroscopy, and copolymer composition was determined with UV‐spectroscopy. The linearization method of Fineman–Ross was employed to obtain the monomer reactivity ratios. The molecular weights and polydispersity indexes were determined by gel permeation chromatography (GPC). Thermogravimetric analyses of polymers were carried out in nitrogen atmosphere. The homo‐ and copolymers were tested for their antimicrobial properties against selected microorganisms. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5227–5234, 2004  相似文献   

17.
The melting and crystallization behavior of polyethylene and isotactic polypropylene containing 1,2‐ or 1,3‐disubstituted cyclopentane units in the main chain has been studied with simultaneous wide‐angle X‐ray diffraction (WAXD) and differential scanning calorimetry. For the ethylene‐based copolymers, the position of a reflection peak in the WAXD patterns shifts to a low angle with the increasing acquired temperature. The temperature dependence on the axial length of the crystal lattice is more marked in the copolymers forming orthorhombic crystals (containing 1,2‐cyclopentane or 5.6 mol % 1,3‐cyclopentane units) than in those forming hexagonal crystals (containing 8.1 mol % 1,3‐cyclopentane units). For the isotactic propylene‐based copolymers, the position of the reflection peaks in the WAXD patterns is independent of the acquired temperature. The proportion of the γ form in the copolymer containing the 1,2‐cyclopentane units is higher than that in the copolymers containing the 1,3‐cyclopentane units. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1457–1465, 2004  相似文献   

18.
Tractable polysilanes were prepared by the copolymerization of a methyl‐n‐propylsilylene (MP) unit into poly(dimethylsilylene), which neither dissolves in common solvents nor melts before decomposition. Although poly(dimethylsilylene‐co‐methyl‐n‐propylsilylene) has poor solubility in the composition range of the dimethylsilylene (DM) unit to the MP unit (DM/MP = 7/3 ∼ 9/1), the copolymers form the columnar mesophase at elevated temperatures. Highly oriented rods were prepared via the extrusion of the copolymers with a circular tube die in a temperature range in which the transition to the columnar mesophase began to occur (70°C when DM/MP = 7/3 and 8/2 and 120°C when DM/MP = 9/1). The extruded rods were characterized in detail by dynamic viscoelasticity and wide‐angle X‐ray diffraction (WAXD) to clarify the structure–mechanical‐property relationship. The orientation functions of the extruded rods were determined by the azimuthal intensity distribution of the WAXD reflection. The orientation function and dynamic storage modulus increased with an increasing extrusion ratio. The dynamic storage modulus at −150°C was 8 ∼ 10 GPa at the highest extrusion ratio and correlated well with the crystal orientation function. The dynamic storage modulus at room temperature was lowered by the structural relaxations at −100 ∼ +30°C, which corresponded to the molecular motion of the rigid molecular chains of the copolymer and the local molecular motion of the MP unit. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 698–706, 2000  相似文献   

19.
Poly(glycolic acid) (PGA) and a series of novel random copolymers of PGA containing 2‐hydroxyisobutyrric acid (PGAPHIB) (HIB unit content from 1.5 to 7.4 mol %) were synthesized and characterized in terms of chemical structure and molecular weight. Afterward, the polyesters were examined by thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction techniques. The copolymers, which displayed a better thermal stability than PGA, at room temperature appeared as semicrystalline materials: the main effect of copolymerization was a lowering in the amount of crystallinity and a decrease of the melting temperature with respect to homopolymer PGA. Baur's equation described well the Tm‐composition data. X‐ray diffraction measurements allowed the identification of the PGA crystalline structure in all cases. After melt quenching, semicrystalline samples were obtained with the exception of PGAPHIB7.4 copolymer. The introduction of HIB units decreased the crystallization rate compared with pure PGA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1901–1910, 2010  相似文献   

20.
The radical ring‐opening copolymerization of 2‐isopropenyl‐3‐phenyloxirane (1) with styrene (St) was examined to obtain the copolymer [copoly(1‐St)] with a vinyl ether moiety in the main chain. The copolymers were obtained in moderate yields by copolymerization in various feed ratios of 1 and St over 120 °C; the number‐average molecular weights (Mn) were estimated to be 1800–4200 by gel permeation chromatography analysis. The ratio of the vinyl ether and St units of copoly(1‐St) was estimated with the 1H NMR spectra and varied from 1/7 to 1/14 according to the initial feed ratio of 1 and St. The haloalkoxylation of copoly(1‐St) with ethylene glycol in the presence of N‐chlorosuccinimide produced a new copolymer with alcohol groups and chlorine atoms in the side group in a high yield. The Mn value of the haloalkoxylated polymer was almost the same as that of the starting copoly(1‐St). The incorporated halogen was determined by elemental analysis. The analytical result indicated that over 88% of the vinyl ether groups participated in the haloalkoxylation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3729–3735, 2000  相似文献   

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