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1.
Chan Woo Lee Kazunari Masutani Tomokazu Kato Yoshiharu Kimura 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1290-1297
A dilactone, 13,26‐dihexyl‐1,14‐dioxacyclohexacosane‐2,15‐dione (12‐HSAD), was synthesized by lipase‐catalyzed reaction of 12‐hydroxystearic acid (12‐HSA) in high yield. It was subjected to the ring‐opening polymerization with various catalysts to obtain poly(12‐hydroxystearate) (PHS). The polymerization system of 12‐HSAD showed an interesting polymerization behavior because of its large ring system. The polymers produced by this polymerization were directly reacted with L ‐lactide to obtain a diblock copolymer of poly(L ‐lactide)‐block‐poly‐(12‐hydroxystearate) (PLLA‐b‐PHS). Characterization of the resultant copolymers was also performed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
2.
Elvira Vidović Doris Klee Hartwig Höcker 《Journal of polymer science. Part A, Polymer chemistry》2007,45(19):4536-4544
Poly(D ,L ‐lactide) and poly(D ,L ‐lactide‐co‐glycolide) with various composition and with one methacrylate and one carboxylate end group were synthesized and grafted onto poly(vinyl alcohol) (PVA) via the carboxylate group. The graft copolymers were crosslinked via the methacrylate groups using a free radical initiator. The polymer networks were characterized by means of NMR and studied qualitatively by means of IR spectroscopy. The influence of the glycolide content in the polyester grafts and of the number of ester units in the grafts on thermal properties and swellability were studied as well. The high swellability in water is characteristic of all hydrogels. Differential scanning calorimetry (DSC) showed a single glass transition temperature that occurs in the range between 51 and 69 °C. Thermogravimetric analysis (TGA) of the networks showed the main loss in weight in the temperature range between 290 and 370 °C. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4536–4544, 2007 相似文献
3.
Ging‐Ho Hsiue Chun‐Liang Lo Ching‐Hao Cheng Che‐Ping Lin Chun‐Kai Huang Hung‐Hao Chen 《Journal of polymer science. Part A, Polymer chemistry》2007,45(4):688-698
A poly(D,L ‐lactide)–bromine macroinitiator was synthesized for use in the preparation of a novel biocompatible polymer. This amphiphilic diblock copolymer consisted of biodegradable poly(D,L ‐lactide) and 2‐methacryloyloxyethyl phosphorylcholine and was formed by atom transfer radical polymerization. Polymeric nanoparticles were prepared by a dialysis process in a select solvent. The shape and structure of the polymeric nanoparticles were determined by 1H NMR, atomic force microscopy, and ζ‐potential measurements. The results of cytotoxicity tests showed the good cytocompatibility of the lipid‐like diblock copolymer poly(2‐methacryloyloxyethyl phosphorylcholine)‐block‐poly(D,L ‐lactide). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 688–698, 2007 相似文献
4.
Hiroyuki Shirahama Akira Tanaka Hajime Yasuda 《Journal of polymer science. Part A, Polymer chemistry》2002,40(3):302-316
Syntheses of copolymers composed of optically active depsipeptides (3,6‐dimethyl‐2,5‐morphorinedione) and L ‐lactide—poly(L ‐3,L ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide), poly(L ‐3,DL ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide), and poly(L ‐3,D ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide)—were examined in an effort to improve the biodegradability and physical properties of homopoly(L ‐lactide). In degradation tests, the copolymers composed of 3,6‐dimethyl‐2,5‐morphorinedione and lactide in the ratios 10/90 to 13/87 exhibited high biodegradability toward proteinase K, whereas a homopolymer, poly(L ‐lactide), exhibited very poor biodegradability (only 50% after 200 h). These polymers composed of 3,6‐dimethyl‐2,5‐morphorinedione/L ‐lactide in 11/89 to 13/87 ratios also degrades rapidly after being in compost for 30 days. The resulting copolymers, however, showed relatively low elongation properties. Therefore, ternary copolymerizations of L ‐3,DL ‐6‐dimethyl‐2,5‐morphorinedione, ?‐caprolactone, and L ‐lactide were explored in an effort to improve their mechanical properties, especially the elongation, and sufficient results were obtained with an approximate ratio of 3/11/86. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 302–316, 2002 相似文献
5.
Jun Shao Zhaohui Tang Jingru Sun Gao Li Xuesi Chen 《Journal of Polymer Science.Polymer Physics》2014,52(23):1560-1567
Linear and four‐armed poly(l ‐lactide)‐block‐poly(d ‐lactide) (PLLA‐b‐PDLA) block copolymers are synthesized by ring‐opening polymerization of d ‐lactide on the end hydroxyl of linear and four‐armed PLLA prepolymers. DSC results indicate that the melting temperature and melting enthalpies of poly (lactide) stereocomplex in the copolymers are obviously lower than corresponding linear and four‐armed PLLA/PDLA blends. Compared with the four‐armed PLLA‐b‐PDLA copolymer, the similar linear PLLA‐b‐PDLA shows higher melting temperature (212.3 °C) and larger melting enthalpy (70.6 J g?1). After these copolymers blend with additional neat PLAs, DSC, and WAXD results show that the stereocomplex formation between free PLA molecular chain and enantiomeric PLA block is the major stereocomplex formation. In the linear copolymer/linear PLA blends, the stereocomplex crystallites (sc) as well as homochiral crystallites (hc) form in the copolymer/PLA cast films. However, in the four‐armed copolymer/linear PLA blends, both sc and hc develop in the four‐armed PLLA‐b‐PDLA/PDLA specimen, which means that the stereocomplexation mainly forms between free PDLA molecule and the inside PLLA block, and the outside PDLA block could form some microcrystallites. Although the melting enthalpies of stereocomplexes in the blends are smaller than that of neat copolymers, only two‐thirds of the molecular chains participate in the stereocomplex formation, and the crystallization efficiency strengthens. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1560–1567 相似文献
6.
Tiantang Fan Jingwen Qin Shengli Lin Wuyou Ye Qing Liu Zhongyong Fan Ye Wang 《先进技术聚合物》2020,31(8):1675-1687
The blends of poly(1,3‐trimethylene carbonate‐b‐(l ‐lactide‐ran‐glycolide)) (PTLG) with poly(d ‐lactide) (PDLA) were prepared via solution‐casting method using CH2Cl2 as solvent. The poly(l ‐lactide) (PLLA) segments of PTLG with PDLA chain constructed as stereocomplex structures and growth stereocomplex crystals of PLA (sc‐PLA). The effects of sc‐PLA crystals on thermal behavior, mechanical properties, thermal decomposition of the PTLG/PDLA blends were investigated, respectively. The differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD) results showed that the total crystallinity of the PTLG/PDLA blends was increased with the PDLA content increasing. Heterogeneous nucleation of sc‐PLA crystals induced crystallization of the PLLA segments in PTLG. The crystallization temperature of samples shifted to 107.5°C for the PTLG/PDLA‐20 blends compared with that of the PTLG matrix, and decreased the half‐time of crystallization. The mechanical measurement results indicated that the tensile strength of the PTLG/PDLA blends was improved from 21.1 MPa of the PTLG matrix to 39.5 MPa of PTLG/PDLA‐20 blends. The results of kinetics of thermal decomposition of the PTLG/PDLA blends by TGA showed that the apparent activation energy of the PTLG/PDLA blends was increased from 59.1 to 72.1 kJ/mol with the increasing of the PDLA content from 3 wt% to 20 wt%, which indicated the enhancement of thermal stability of the PTLG/PDLA blends by addition of PDLA. Furthermore, the biocompatibility of the PTLG/PDLA blends cultured with human adipose‐derived stem cells was evaluated by CCK‐8 and live/dead staining. The experiment results proved the PTLG/PDLA blends were a kind of biomaterial with excellent physical performances with very low cytotoxicity. 相似文献
7.
Catherine Lefay David Glé Marion Rollet Jérôme Mazzolini Denis Bertin Stéphane Viel Christina Schmid Christophe Boisson Franck D'Agosto Didier Gigmes Christopher Barner‐Kowollik 《Journal of polymer science. Part A, Polymer chemistry》2011,49(3):803-813
Poly(styrene) macromercaptanes (Mn = 1900, 3600, and 6100 g mol?1, PDI ≈ 1.2) derived from thiocarbonyl thio capped polymers prepared via reversible addition fragmentation chain transfer polymerization were employed to initiate the ring opening polymerization (ROP) of D ,L ‐lactide under conditions of organo‐catalyis employing 4,4‐dimethylaminopyridine. Poly(styrene)‐block‐poly(lactide) polymers of number average molecular weights up to 25,000 g mol?1 (PDI ≈ 1.2 to 1.6) were obtained and characterized via multiple detection size exclusion chromatography (SEC) using refractive index as well as UV detection. In addition, diffusion ordered nuclear magnetic resonance and liquid chromatography at critical conditions (of both polystyrene as well as poly(lactide) were employed to assess the copolymers' structure. Furthermore, it was demonstrated that polyethylenes capped with a thiol moiety can also be readily chain extended in a ROP employing D ,L ‐lactide, evidenced via NMR and high temperature SEC. This study indicates that the direct use of macromercaptantes is indeed a methodology to switch from a radical to a ROP process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
8.
Sungil Moon Masatoshi Iji 《Journal of polymer science. Part A, Polymer chemistry》2008,46(13):4433-4441
A new poly(butylene succinate) (PBS)‐grafted vapor grown carbon fiber (VGCF)/poly(L ‐lactide) (PLLA) nanocomposites were successfully prepared by an in situ condensation reaction between PBS (Mw = 6,000) and surface oxidized VGCF, followed by direct melt mixing technique, and their mechanical and thermal properties were evaluated. Fourier transform infrared spectroscopy and scanning electron microscopy studies indicate a chemical interaction between the PBS and the surface of VGCF. It was found that the maximum tensile strength and modulus of PBS‐grafted VGCF/PLLA nanocomposites were 135 MPa (27% increase relative to neat PLLA) and 4,400 MPa (29% increase relative to neat PLLA), respectively. The results indicate that significant improvement in the mechanical properties can be accomplished by optimizing the surface modification conditions for VGCF. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4433–4441, 2008 相似文献
9.
Jun Luo Fei Huo Hui Lin Zhouli Lin Zhengjian Chen Fang Yuan Hongliang Jiang Hongjun Wang Kehua Tu Dingrong Liu Songwei Tan Li‐Qun Wang 《Journal of Polymer Science.Polymer Physics》2012,50(18):1277-1285
Commercial poly(L ‐lactide) is typically heterogeneous in chain structure due to the existence of a small amount of D ‐lactyl units that are produced by the racemization reactions during the synthesis. In this article, the stereochemical heterogeneity of two commercial poly(L ‐lactide) was investigated with temperature rising elution fractionation (TREF) and successive self‐nucleation/annealing (SSA) thermal fractionation. For both samples, three fractions were collected and characterized with rotatory power analysis and DSC. The fractions show distinct optical purity and DSC results, which reflect the structure differences among them directly. After SSA treatment, the observation of multiple endotherms for each physically separated fraction confirms the fractionated sample contains a heterogeneous intermolecular and intramolecular distribution of defects. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
10.
Poly(L ‐lactide) (PLLA)/poly(butylene succinate‐co‐butylene adipate) (PBSA) blends were compounded with Cloisite 25A® (C25A) and C25A functionalized with epoxy groups, respectively. Epoxy groups on the surface of C25A were introduced by treating C25A with (glycidoxypropyl)trimethoxy silane (GPS) to produce so called Twice Functionalized Organoclay (TFC). Variation of morphology and properties of PLLA/PBSA/C25A composites was investigated before and after the treatment with GPS. The morphological structure of the composites was analyzed by using X‐ray diffractometry (XRD) and transmission electron microscopy (TEM). The silicate layers of PLLA/PBSA/TFC were exfoliated to a larger extent than PLLA/PBSA/C25A. Incorporation of the epoxy groups on C25A improved significantly elongation at break as well as tensile modulus and tensile strength of PLLA/PBSA/C25A. The larger amount of exfoliation of the silicate layers in PLLA/PBSA/TFC as compared with that in PLLA/PBSA/C25A was attributed to the increased interfacial interaction between the polyesters and the clay due to chemical reaction. Thermo gravimetric analysis revealed that both T5%, which was the temperature corresponding to 5% weight loss, and activation energy of thermal decomposition of PLLA/PBSA/TFC were far superior to those of PLLA/PBSA/C25A as well as to those of PLLA/PBSA, indicating that the composites with exfoliated silicate layers were more thermally stable than those with intercalated silicate layers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 478–487, 2005 相似文献
11.
Yuushou Nakayama Takamichi Inaba Yosuke Toda Ryo Tanaka Zhengguo Cai Takeshi Shiono Hiroyuki Shirahama Chikara Tsutsumi 《Journal of polymer science. Part A, Polymer chemistry》2013,51(20):4423-4428
l ‐Lactide (l ‐LA) was polymerized in the presence of N‐methyldiethanolamine as an initiator and Sn(Oct)2 as a catalyst to give hydroxy‐telechelic poly(l ‐lactide) (PLLA‐diol) bearing a tertiary amine group at the center of the polymer chain. Successive chain extension of the PLLA‐diol with hexamethylene diisocyanate afforded PLLA‐based poly(ester‐urethane)s (PEU) with equally spaced tertiary amine groups. Treatment of the PEU with iodomethane converted tertiary amine groups to quaternary ammonium groups to give cationic ionomers (PEU‐MeI). The thermal, mechanical, hydrophilic, and biodegradation properties of the obtained polymers were investigated. The thermal properties of the PEUs and the PEU‐MeIs were similar each other. The PEU‐MeIs exhibited higher tensile modulus than those of the starting PEUs. The contact angles of water on the PEU‐MeIs were lower than those of the PEUs with similar NMDA content indicating their higher hydrophilicity. In compost degradation tests, the PEU‐MeIs showed slower degradation than those of the PEUs. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4423–4428 相似文献
12.
Gisha Elizabeth Luckachan C. K. S. Pillai 《Journal of polymer science. Part A, Polymer chemistry》2006,44(10):3250-3260
Novel multiblock poly(ester amide)s containing poly(L ‐lactide) and cycloaliphatic amide segments were synthesized from telechelic oligomer of α,ω‐hydroxyl terminated poly(L ‐lactide), 1,3‐cyclohexylbis(methylamine), and sebacoylchloride by the “two‐step” interfacial polycondensation method. The blocky nature of PEAs was established by FTIR and 1H NMR spectroscopies. The effect of relative content of ester and amide segments on the crystallization nature of PEAs was investigated by WAXD and DSC analyses. PEAs having lower content of PLLA, PEA 1 and PEA 2, showed a crystallization pattern analogous to polyamides, whereas PEA 3, having higher content of PLLA, showed two crystalline phases characterized by polyester and polyamide segments. Random nature of PEAs was observed from single Tg values. Biodegradation studies using the enzyme lipase from Candida Cylindracea showed higher degradation rate for PEA 3 than that for PEA 1 and PEA 2. FTIR, 1H NMR, and DSC analyses of the degraded products indicated the involvement of ester linkages in the degradation process. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3250–3260, 2006 相似文献
13.
Karina A. George François Schué Traian V. Chirila Edeline Wentrup‐Byrne 《Journal of polymer science. Part A, Polymer chemistry》2009,47(18):4736-4748
Using an in situ‐generated calcium‐based initiating species derived from pentaerythritol, the bulk synthesis of well‐defined four‐arm star poly(L ‐lactide) oligomers has been studied in detail. The substitution of the traditional initiator, stannous octoate with calcium hydride allowed the synthesis of oligomers that had both low PDIs and a comparable number of polymeric arms (3.7–3.9) to oligomers of similar molecular weight. Investigations into the degree of control observed during the course of the polymerization found that the insolubility of pentaerythritol in molten L ‐lactide resulted in an uncontrolled polymerization only when the feed mole ratio of L ‐lactide to pentaerythritol was 13. At feed ratios of 40 and greater, a pseudoliving polymerization was observed. As part of this study, in situ FT‐Raman spectroscopy was demonstrated to be a suitable method to monitor the kinetics of the ring‐opening polymerization of lactide. The advantages of using this technique rather than FTIR‐ATR and 1H NMR for monitoring L ‐lactide consumption during polymerization are discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4736–4748, 2009 相似文献
14.
Julien Ramier Estelle Renard Daniel Grande 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1445-1455
Microwave (MW)‐assisted ring‐opening polymerization (ROP) provides a rapid and straightforward method for engineering a wide array of well‐defined poly(3‐hydroxyalkanoate)‐b‐poly(D,L ‐lactide) (PHA‐b‐PLA) diblock copolymers. On MW irradiation, the bulk ROP of D,L ‐lactide (LA) could be efficiently triggered by a series of monohydroxylated PHA‐based macroinitiators previously produced via acid‐catalyzed methanolysis of corresponding native PHAs, thus affording diblock copolyesters with tunable compositions. The dependence of LA polymerization on temperature, macroinitiator structure, irradiation time, and [LA]0/[PHA]0 molar ratio was carefully investigated. It turned out that initiator efficiency values close to 1 associated with conversions ranging from 50 to 85% were obtained only after 5 min at 115 °C. A kinetic investigation of the MW‐assisted ROP of LA gave evidence of its “living”/controlled character under the experimental conditions selected. Structural analyses and thermal properties of biodegradable diblock copolyesters were also performed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
15.
Ming‐Hsi Huang Jean Coudane Suming Li Michel Vert 《Journal of polymer science. Part A, Polymer chemistry》2005,43(18):4196-4205
Methylated and pegylated poly(lactide)‐block‐poly(ε‐caprolactone)‐block‐poly(lactide) copolymers, PLA–P(CL‐co‐CLCH3)–PLA and PLA–P(CL‐co‐CLPEG)–PLA, were prepared in three steps: combining the formation of carbanion‐bearing dihydroxylated‐PCL, the coupling of iodomethane or bromoacetylated α‐hydroxyl‐ω‐methoxy‐poly(ethylene glycol) onto the carbanionic PCL, and finally the ring opening polymerization of DL ‐lactide initiated by the preformed grafted diOH‐PCL copolymers. The resulting block copolymers exhibited lower crystallinity, melting temperature, and hydrophobicity with respect to the original PCL. Degradation of the grafted copolymers was investigated in the presence of Pseudomonas cepacia lipase and compared with that of the triblock copolymer precursor. It is shown that the presence of the grafted substituents affected the enzymatic degradation of PCL segments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4196–4205, 2005 相似文献
16.
Sang Hyo Lee Jae Min Oh Jin Soo Son Jung Won Lee Byung Soo Kim Gilson Khang Dong Keun Han Jae Ho Kim Hai Bang Lee Moon Suk Kim 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5917-5922
Polymerization of L ‐lactide (LA) was performed in the presence of trifluoromethanesulfonic acid (CF3SO3H) via an activated monomer mechanism to synthesize various block copolymers composed of polyethyleneglycol (PEG) and poly(L ‐lactide) (PLLA). The PLLAs obtained had molecular weights close to theoretical values calculated from LA/PEG molar ratios and exhibited monomodal GPC curves. A 1H NMR spectroscopic study showed that the LA carbonyl carbon signal exhibited a change in chemical shift to lower field, caused by electron delocalization of the carbonyl carbon by CF3SO3H. We successfully prepared PEG and PLLA block copolymers using this activated monomer mechanism. We concluded that synthesis proceeded by LA ring‐opening polymerization caused by PEG in the presence of CF3SO3H to yield PEG and PLLA block copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5917–5922, 2009 相似文献
17.
Amol V. Janorkar Sarah E. Proulx Andrew T. Metters Douglas E. Hirt 《Journal of polymer science. Part A, Polymer chemistry》2006,44(22):6534-6543
The major objective of this research was to modify the surface characteristics of poly(L ‐lactide) (PLA) by grafting a combination of hydrophilic polymers to produce a continuum of hydrophilicity. The PLA film was solvent cast, and the film surfaces were activated by ultra violet (UV) irradiation. A single monomer or combination of two monomers, selected from vinyl acetate (VAc), acrylic acid (AA), and acrylamide (AAm), were then grafted to the PLA film surface using a UV induced photopolymerization process. The film surfaces resulting from each reaction step were analyzed using ATR‐FTIR spectroscopy and contact angle goniometry. Results showed that AAm dominated the hydrophilicity of the film surface when copolymerized with VAc or AA, while the water contact angles for PLA films grafted with poly(vinyl acetate‐co‐acrylic acid) varied more gradually with feed composition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6534‐6543, 2006 相似文献
18.
Michael J. Isaacman Weibin Cui Luke S. Theogarajan 《Journal of polymer science. Part A, Polymer chemistry》2014,52(21):3134-3141
Nitrile oxide 1,3 dipolar cycloaddition is a simple and powerful coupling methodology. However, the self‐dimerization of nitrile oxides has prevented the widespread use of this strategy for macromolecular coupling. By combining an in situ nitrile oxide generation with a highly reactive activated dipolarophile, we have overcome these obstacles and present a metal‐free macromolecular coupling strategy for the modular synthesis of several ABA triblock copolymers. Nitrile oxides were generated in situ from chloroxime terminated poly(dimethylsiloxane) B‐blocks and coupled with several distinct hydrophilic (poly(2‐methyloxazoline) and poly(ethylene glycol)), and poly(N‐isopropylacrylamide) or hydrophobic (poly(l ‐lactide) A‐blocks terminated in activated dipolarophiles in a rapid fashion with high yield. This methodology overcomes many drawbacks of previously reported metal‐free methods due to its rapid kinetics, versatility, scalability, and ease of introduction of necessary functionality. Nitrile oxide cycloaddition should find use as an attractive macromolecular coupling strategy for the synthesis of biocompatible polymeric nanostructures. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3134–3141 相似文献
19.
Miscible blends of poly(ethylene oxide) with brush copolymers of poly(vinyl alcohol)‐graft‐poly(l‐lactide) 下载免费PDF全文
Ainhoa Lejardi Jose‐Ramon Sarasua Agustin Etxeberria Emilio Meaurio 《Journal of Polymer Science.Polymer Physics》2016,54(13):1217-1226
Even though poly(ethylene oxide) (PEO) is immiscible with both poly(l ‐lactide) (PLLA) and poly(vinyl alcohol) (PVA), this article shows a working route to obtain miscible blends based on these polymers. The miscibility of these polymers has been analyzed using the solubility parameter approach to choose the proper ratios of the constituents of the blend. Then, PVA has been grafted with l ‐lactide (LLA) through ring‐opening polymerization to obtain a poly(vinyl alcohol)‐graft‐poly(l ‐lactide) (PVA‐g‐PLLA) brush copolymer with 82 mol % LLA according to 1H and 13C NMR spectroscopies. PEO has been blended with the PVA‐g‐PLLA brush copolymer and the miscibility of the system has been analyzed by DSC, FTIR, OM, and SEM. The particular architecture of the blends results in DSC traces lacking clearly distinguishable glass transitions that have been explained considering self‐concentration effects (Lodge and McLeish) and the associated concentration fluctuations. Fortunately, the FTIR analysis is conclusive regarding the miscibility and the specific interactions in these systems. Melting point depression analysis suggests that interactions of intermediate strength and PLOM and SEM reveal homogeneous morphologies for the PEO/PVA‐g‐PLLA blends. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1217–1226 相似文献
20.
Yanli Li Haiyan Wu Yong Wang Li Liu Liang Han Jun Wu Fangming Xiang 《Journal of Polymer Science.Polymer Physics》2010,48(5):520-528
This work reported the crystallization behaviors of poly(L ‐lactide) (PLLA) with the presence of polyethylene glycol (PEG) and/or functionalized multiwalled carbon nanotubes (FMWCNTs). The crystallization behaviors occurred in the different conditions, including nonisothermal, isothermal and during the annealing process, were analyzed comparatively using differential scanning calorimetry, wide angle X‐ray diffraction, and polarized optical microscope. The results show that PEG as an efficient plasticizer of PLLA enhances the mobility of PLLA chain segments, which leads to the decrease of glass transition temperature and the enhancement of crystallization ability of PLLA. FMWCNTs as a nucleating agent of PLLA crystallization promote the crystallization of PLLA apparently. With the presence of PEG and FMWCNTs, the crystallization of PLLA is well improved in all conditions, indicating the synergistic effects of PEG and FMWCNTs on PLLA crystallization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 520–528, 2010 相似文献