Synthesis,characterization, and hydrolytic degradation of biodegradable poly(ether ester)‐urethane copolymers based on ε‐caprolactone and poly(ethylene glycol)

In this article, a new kind of biodegradable poly(ε‐caprolactone)‐poly(ethylene glycol)‐poly(ε‐caprolactone)‐based polyurethane (PCEC‐U) copolymers were successfully synthesized by melt‐polycondensation method from ε‐caprolactone (ε‐CL), poly(ethylene glycol) (PEG), 1,4‐butanediol (BD), and isophorone diisocyanate (IPDI). The obtained copolymers were characterized by ¹H‐nuclear magnetic resonance (¹H‐NMR), FTIR, and gel permeation chromatography (GPC). Thermal properties of PCEC‐U copolymers were studied by DSC and TGA/DTG under nitrogen atmosphere. Water absorption and hydrolytic degradation behavior of these copolymers were also investigated. Hydrolytic degradation behavior was studied by weight loss method. ¹H‐NMR and GPC were also used to characterize the hydrolytic degradation behavior of PCEC‐U copolymers. The molecular weight of PCL block and PEG block in soft segment and the content of hard segment strongly affected the water absorption and hydrolytic degradation behavior of PCEC‐U copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Use of modified poly(ϵ‐caprolactone) in the compatibilization of poly(ϵ‐caprolactone)/maize starch blends

In this work, the compatibilization of a poly(?‐caprolactone) with a number‐average molecular weight of 120,000 g/mol (PCL¹²⁰) and maize starch was investigated by the addition of a chemically modified poly(?‐caprolactone). Two types of blends were prepared by melt extrusion. In type A blends, low‐molecular‐weight compatibilizers were used: (1) a poly(?‐caprolactone) with a number‐average molecular weight of 10,000 g/mol that was reacted with maleic anhydride to obtain chains terminating in carboxylic groups and (2) low‐molecular‐weight poly(?‐caprolactone)s (number‐average molecular weights of 600 and 2000 g/mol) with one pendant carboxylic group within the chains. With these groups of blends, tensile testing and scanning electron microscopy demonstrated that the compatibilizers were generally effective in inducing a better dispersion for a 60/40 poly(?‐caprolactone)/maize starch blend with a compatibilizer, improving the mechanical properties in comparison with uncompatibilized blends. The blends with 30% starch were not improved by the addition of compatibilizer, and this may be related to the rheology of the blends during preparation. In type B blends, high‐molecular‐weight compatibilizers were prepared through the grafting of variable amounts of acrylic acid or maleic anhydride to PCL¹²⁰ chains. The best compatibilizer action was obtained with 0.7 wt % maleic anhydride grafted to PCL¹²⁰ because both the dispersion and mechanical properties were further improved in comparison with uncompatibilized blends and type A blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,characterization and crosslinking of functional star‐shaped poly(ε‐caprolactone)

Star‐shaped low molecular weight poly(ε‐caprolactone)s (PCLs) were synthesized and functionalized with crosslinkable terminal groups for subsequent crosslinking. The ε‐caprolactone (CL) prepolymers were polymerized by ring‐opening in the presence of polyglycerine (PGL) as an initiator (1, 3 and 5 mol%) and Sn(II)2‐ethylhexanoate as a catalyst. Characterization of the prepolymer by ¹³C/¹H nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) revealed a six‐armed star‐shaped structure for the prepolymer with the molecular weight controlled by the ratio of PGL and CL. Functionalization of the hydroxyl‐terminated prepolymer was carried out with maleic or itaconic anhydride. In both cases, the characterization of the functionalized prepolymer showed that the hydroxyl groups were completely substituted. The functionalized PCLs were successfully crosslinked through the reaction of double bonds. The crosslinking was induced either thermally with organic peroxide or photochemically with a photosensitive initiator. Characterization of the crosslinked PCLs by Soxhlet extraction, DSC and FTIR showed that the itaconic double bond was much more reactive in thermal crosslinking than the maleic double bond. Thus, the crosslinked prepolymers that were functionalized with itaconic double bonds achieved a gel content of about 90%. A gel content of 100% was achieved with several compositions where crosslinking agents were employed. © 2002 Society of Chemical Industry     

Synthesis and characterization of new biodegradable fluorescing poly(amide‐anhydrides)

Biodegradable/alternate/poly(amide‐anhydrides), [? C(O)PhNHC(O)(CH₂) _nC(O)O? ] _x, were synthesized by melt polycondensation, where n was 2, 3 or 4. The polymers have been characterized by NMR, DSC, wide‐angle X‐ray diffractometry and fluorometry. All the polymers are amorphous and their T_g ranges from 60 to 80 °C. Poly(p‐(carboxyethylformamido)benzoic anhydride) (PCEFB) as a film or in solution in chloroform can emit strong fluorescence, which was not observed for the other two polyanhydrides (n = 3, 4). The maximum emission wavelength varies with the excitation wavelength, 480 and 520 nm at the excitation wavelength of 470 nm, and 430 nm at 356 nm. In addition, the fluorescence intensities increase linearly with the molecular weight of PCEFB. Such inherent fluorescing properties of PCEFB, together with its biodegradability, make the polymer a potential visible matrix for drug delivery. © 2001 Society of Chemical Industry     

Functionalized multiarm poly(ϵ‐caprolactone)s: Synthesis,structure analysis,and network formation

The purpose of this research was to synthesize and characterize a novel class of four‐arm, star‐shape biodegradable polymers having double‐bond functionality as a precursor for free‐radical polymerization, with unsaturated monomers or macromers or photocrosslinking for network formation. The synthesis involved two basic steps. First, hydroxyl‐functionalized four‐arm poly(?‐caprolactone)s (PPCL‐OH) were synthesized by the ring‐opening polymerization of ?‐caprolactone in the presence of pentaerythritol and stannous octoate. Second, double‐bond–functionalized four‐arm poly(?‐caprolactone)s (PPCL‐Ma) were synthesized by reacting PPCL‐OH with maleic anhydride in the melt at 130°C. Quantitative conversion of hydroxyl functionality in PPCL‐OH to double‐bond functionality was achieved for low molecular weight PPCL‐OH. Both the PPCL‐OH and the PPCL‐Ma were characterized by FTIR, ¹H‐NMR, ¹³C‐NMR, SEC, and DSC. The capability of the double‐bond–functionalized four‐arm poly(?‐caprolactone)s (PPCL‐Ma) to form network structures was preliminarily shown by photocrosslinking PPCL‐Ma. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2296–2306, 2002     

Synthesis,degradation, and drug delivery of cycloaliphatic poly(ester anhydride)s

The high melting point of poly(1,4‐cyclohexanedicarboxylic anhydride) [poly(CHDA)] is a disadvantage, in that it is intractable in the melting process of a drug delivery system. This report relates to diols introduced into the polyanhydride main chain to decrease its melting point. Various poly(ester anhydride)s containing ethylene glycol, 1,3‐propanediol, 1,4‐butanediol, or 1,6‐hexandiol [poly(CHDA–XDO)] were synthesized by the esterification reaction and melt polycondensation. FTIR, DSC, WAXD, and intrinsic viscosity of polymers were recorded and hydrolytic degradation, as well as in vitro drug delivery, was conducted. The results show that the samples are stable in an anhydrous environment at room temperature and degrade in water following a surface erosion mechanism. The degradation period of poly(CHDA–XDO) ranged from 130 to 320 h as a result of the different diols and amounts of XDO introduced. The in vitro drug delivery gave 130–350 h of stable delivery along with the typical surface erosion mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2509–2514, 2002     

Multicarboxylic aromatic acid core initiator for the synthesis of star‐shaped poly(ϵ‐caprolactone) with carboxyl end groups

We successfully carried out the ring‐opening polymerization of ?‐caprolactone with 1,3,5‐benzenetricarboxylic acid and 1,2,4,5‐benzenetetracarboxylic acid as the core initiators at 225°C in bulk, and three‐armed and four‐armed star poly(?‐caprolactone)s [poly(?‐CL)s] with carboxyl end groups were obtained. No transesterification, which would have led to a decrease in the molecular weight of poly(?‐CL), was found. The effects of the polymerization conditions on the polymerization are discussed; the poly(?‐CL)s were characterized by ¹H‐NMR, gel permeation chromatography, and thermogravimetric analysis in detail. A mechanism of alkyl–oxygen bond scission by the nucleophilic attack of the carboxyl anions via hydrogen proton transfer is presented for this system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3713–3717, 2006     

Melt electrospinning writing of three‐dimensional star poly(ϵ‐caprolactone) scaffolds

In the last decade, the melt‐electrospinning technique has gained attention for the production of highly porous microfibrous tissue engineering scaffolds. The possibility of processing polymers without the use of organic solvents is one of the main advantages over solution electrospinning. In this study, computer‐controlled melt‐electrospinning of a commercial poly(?‐caprolactone) and of two batches with different molecular weights of a three‐arm star poly(?‐caprolactone) by means of a screw‐extruder‐based additive manufacturing system is reported. Experimental parameters such as processing temperature, extrusion flow rate and applied voltage were studied and optimized in order to obtain non‐woven meshes with uniform fibre morphology. Applying the optimized parameters, three‐dimensional scaffolds were produced using a layer‐by‐layer approach (0 ? 90° lay‐down pattern). © 2013 Society of Chemical Industry     

Catalyzed chain extension of poly(butylene adipate) and poly(butylene succinate) with 2,2′‐(1,4‐phenylene)‐bis(2‐oxazoline)

Low‐molecular‐weight HOOC‐terminated poly(butylene adipate) prepolymer (PrePBA) and poly(butylene succinate) prepolymer (PrePBS) were synthesized through melt‐condensation polymerization from adipic acid or succinic acid with butanediol. The catalyzed chain extension of these prepolymers was carried out at 180–220°C with 2,2′‐(1,4‐phenylene)‐bis(2‐oxazoline) as a chain extender and p‐toluenesulfonic acid (p‐TSA) as a catalyst. Higher molecular weight polyesters were obtained from the catalyzed chain extension than from the noncatalyzed one. However, an improperly high amount of p‐TSA and a high temperature caused branching or a crosslinking reaction. Under optimal conditions, chain‐extended poly(butylene adipate) (PBA) with a number‐average molecular weight up to 29,600 and poly(butylene succinate) (PBS) with an intrinsic viscosity of 0.82 dL/g were synthesized. The chain‐extended polyesters were characterized by IR spectroscopy, ¹H‐NMR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis, wide‐angle X‐ray scattering, and tensile testing. DSC, wide‐angle X‐ray scattering, and thermogravimetric analysis characterization showed that the chain‐extended PBA and PBS had lower melting temperatures and crystallinities and slower crystallization rates and were less thermally stable than PrePBA and PrePBS. This deterioration of their properties was not harmful enough to impair their thermal processing properties and should not prevent them from being used as biodegradable thermoplastics. The tensile strength of the chain‐extended PBS was about 31.05 MPa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Copolymers based on poly(butylene terephthalate) and polycaprolactone‐block‐polydimethylsiloxane‐block‐polycaprolactone

A series of novel thermoplastic elastomers, based on poly(butylene terephthalate) (PBT) and polycaprolactone‐block‐polydimethylsiloxane‐block‐polycaprolactone (PCL‐PDMS‐PCL), with various mass fractions, were synthesized through melt polycondensation. In the synthesis of the poly(ester‐siloxane)s, the PCL blocks served as a compatibilizer for the non‐polar PDMS blocks and the polar comonomers dimethyl terephthalate and 1,4‐butanediol. The introduction of PCL‐PDMS‐PCL soft segments resulted in an improvement of the miscibility of the reaction mixture and therefore in higher molecular weight polymers. The content of hard PBT segments in the polymer chains was varied from 10 to 80 mass%. The degree of crystallinity of the poly(ester‐siloxane)s was determined using differential scanning calorimetry and wide‐angle X‐ray scattering. The introduction of PCL‐PDMS‐PCL soft segments into the polymer main chains reduced the crystallinity of the hard segments and altered related properties such as melting temperature and storage modulus, and also modified the surface properties. The thermal stability of the poly(ester‐siloxane)s was higher than that of the PBT homopolymer. The inclusion of the siloxane prepolymer with terminal PCL into the macromolecular chains increased the molecular weight of the copolymers, the homogeneity of the samples in terms of composition and structure and the thermal stability. It also resulted in mechanical properties which could be tailored. Copyright © 2010 Society of Chemical Industry     

Biodegradable studies of poly(trimethylenecarbonate‐ε‐caprolactone)‐block‐poly(p‐dioxanone), poly(dioxanone), and poly(glycolide‐ε‐caprolactone) (Monocryl®) monofilaments

The aim of the study was to investigate the mechanical properties and biodegradability of poly(trimethylenecarbonate‐ε‐caprolactone)‐block‐poly(p‐dioxanone) [P(TMC‐ε‐CL)‐block‐PDO] in comparison with poly(p‐dioxanone) and poly(glycolide‐ε‐caprolactone) (Monocryl®) monofilaments in vivo and in vitro. P(TMC‐ε‐CL)‐block‐PDO copolymer and poly(p‐dioxanone) were prepared by using ring‐opening polymerization reaction. The monofilament fibers were obtained using conventional melt spun methods. The physicochemical and mechanical properties, such as viscosity, molecular weight, crystallinity, and knot security, were studied. Tensile strength, breaking strength retention, and surface morphology of P(TMC‐ε‐CL)‐block‐PDO, poly(p‐dioxanone), and Monocryl monofilament fibers were studied by immersion in phosphate‐buffered distilled water (pH 7.2) at 37°C and in vivo. The implantation studies of absorbable suture strands were performed in gluteal muscle of rats. The polymers, P(TMC‐ε‐CL)‐block‐PDO, poly(p‐dioxanone), and Monocryl, were semicrystalline and showed 27, 32, and 34% crystallinity, respectively. Those mechanical properties of P(TMC‐ε‐CL)‐block‐PDO were comparatively lower than other polymers. The biodegradability of poly(dioxanone) homopolymer is much slower compared with that of two copolymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 737–743, 2006     

Synthesis,crystallinity and degradation properties of biodegradable poly[(sebacic anhydride)‐co‐caprolactone] triblock copolymers

BACKGROUND: A series of novel biodegradable poly[(sebacic anhydride)‐co‐caprolactone] (PSA‐co‐PCL) triblock copolymers were prepared by melt condensation of acylated PSA and monofunctional hydroxyl‐terminated PCL prepolymers. These copolymers could be used as novel drug delivery carriers with expected good drug permeability due to the PCL component. The degradation rate and mode can be modulated by varying the ratio of monomers in the copolymer. RESULTS: The homopolymers and copolymers were characterized using ¹H NMR, gel permeation chromatography and differential scanning calorimetry (DSC). ¹H NMR confirmed the formation of triblock copolymers that comprise a middle PSA block and two side PCL blocks. DSC revealed that the melting temperature and degree of crystallinity for both sebacic anhydride (SA) and caprolactone (CL) components are strongly composition dependent, implying the hindrance effect of the two components on the crystallinity. In vitro degradation experiments showed that the mass loss is significantly accelerated for samples in base buffer solution and more rapid for the copolymers with a higher SA content. Scanning electron microscopy revealed that for SA‐rich copolymer, PSA(80 wt%)‐co‐PCL, surface erosion dominated the degradation mode of the sample. In contrast, for CL‐rich copolymer, PSA(20 wt%)‐co‐PCL, a micropore structure developed at a degradation time of 155 h along the edges of the sample, owing to the hydrolysis of SA. CONCLUSION: It is concluded that the rate and mode of degradation of these copolymers can be tuned by varying the composition of the copolymers. Copyright © 2007 Society of Chemical Industry     

Part 7. Effects of poly(L‐lactide‐co‐ϵ‐caprolactone) on morphology,structure, crystallization,and physical properties of blends of poly(L‐lactide) and poly(ϵ‐caprolactone)

Blended films of poly(L ‐lactide) [ie poly(L ‐lactic acid)] (PLLA) and poly(?‐caprolactone) (PCL) without or mixed with 10 wt% poly(L ‐lactide‐co‐?‐caprolactone) (PLLA‐CL) were prepared by solution‐casting. The effects of PLLA‐CL on the morphology, phase structure, crystallization, and mechanical properties of films have been investigated using polarization optical microscopy, scanning electron microscopy, differential scanning calorimetry and tensile testing. Addition of PLLA‐CL decreased number densities of spherulites in PLLA and PCL films, and improved the observability of spherulites and the smoothness of cross‐section of the PLLA/PCL blend film. The melting temperatures (T_m) of PLLA and PCL in the films remained unchanged upon addition of PLLA‐CL, while the crystallinities of PLLA and PCL increased at PLLA contents [X_PLLA = weight of PLLA/(weight of PLLA and PCL)] of 0.4–0.7 and at most of the X_PLLA values, respectively. The addition of PLLA‐CL improved the tensile strength and the Young modulus of the films at X_PLLA of 0.5–0.8 and of 0–0.1 and 0.5–0.8, respectively, and the elongation at break of the films at all the X_PLLA values. These findings strongly suggest that PLLA‐CL was miscible with PLLA and PCL, and that the dissolved PLLA‐CL in PLLA‐rich and PCL‐rich phases increased the compatibility between these two phases. © 2003 Society of Chemical Industry     

Crosslinkable poly(lactic acid)‐based materials: Biomass‐derived solution for barrier coatings

The demand for biobased barrier packaging alternatives is constantly growing. Poly(lactic acid) (PLA)‐based polymers are one of the most extensively studied biomass‐derived synthetic polymers; however, they typically lack water‐barrier properties. We synthesized a copolymer of d ,l ‐lactic acid, 1,4‐butanediol, and itaconic acid [poly(d ,l ‐lactic acid–1,4‐butanediol–itaconic acid) (PLABDIA)] via bulk polycondensation. The radical crosslinking reactions of the synthesized polymer were investigated with bulk crosslinking trials to find a formulation that was suitable for a rapidly crosslinkable barrier coating. The crosslinking efficiency was tested with methacrylate and acrylate crosslinkers together with peroxide radical initiators. Poly(ethylene glycol) diacrylate (number‐average molecular weight = 250 g/mol) together with dilauroyl peroxide proved to be the best crosslinker–initiator combination. An aqueous dispersion of PLABDIA was prepared with a thermomechanical method and applied to commercial boxboard on a pilot‐scale line coater. With a coating weight of 10 g/m², a water vapor transmission rate of 22.8 g/m²d was achieved, and this coating outperformed commercial extruded PLA coatings. The samples also showed very good grease resistance and would, therefore, be a good solution for the packaging of dry and fatty goods. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44326.     

Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex

A series of poly(?‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by ¹H NMR, GPC, WAXD, and DSC. The ¹H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and in vitro degradation properties of poly[(tetramethylene carbonate)‐co‐(sebacic anhydride)]

A novel poly[(tetramethylene carbonate)‐co‐(sebacic anhydride)] (PTCSA) was synthesized by the melt polycondensation reaction of sebacic acid (SA) and the dicarboxylic acid which derived from oligo(tetramethylene carbonate) diol via the corresponding mixed anhydrides. The copolymer structure was confirmed by means of FTIR and [¹H] NMR spectra. DSC analysis showed PTCSA was semicrystalline polymer which had low T_g (<?30 °C). The measurements of contact angles indicated that the hydrophobicity of PTCSA increased as the content of carbonate segments increased. In vitro degradation of PTCSA was performed in lipase‐free and lipase‐containing phosphate‐buffer saline (0.1 M, pH 7.4) at 37 °C. It was found that the degradation rate of PTCSA increased with the amount of SA. After 7 days of degradation in lipase‐free phosphate‐buffer saline, the weight loss of PTCSA was 74, 49 and 22% for 80, 58 and 32 mol% SA contained samples, respectively. The weight loss of PTCSA increased rapidly in the first week, then slowed down but could be greatly enhanced by lipase. After 3 weeks of degradation with or without lipase, the weight loss of PTCSA was 66 and 52% for 58 mol% SA‐containing samples, respectively. The size of the samples was gradually reduced and the surface became coarse. It was also found that the molecular weights of the outer layer were lower than those of the inner layer of the samples after degradation. The results suggested that PTCSA was some kind of biodegradation and surface‐erosion material. © 2001 Society of Chemical Industry     

Synthesis and hydrophilicity of poly(butylene 2,6‐naphthalate)/poly(ethylene glycol) copolymers

Poly(butylene 2,6‐naphthalate) (PBN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two‐step melt copolymerization process of dimethyl‐2,6‐naphthalenedicarboxylate (2,6‐NDC) with 1,4‐butanediol (BD) and PEG. The copolymers produced had different PEG molecular weights and contents. The structures, thermal properties, and hydrophilicities of these copolymers were studied by ¹H NMR, DSC, TGA, and by contact angle and moisture content measurements. In particular, the intrinsic viscosities of PBN/PEG copolymers increased with increasing PEG molecular weights, but the melting temperatures (T_m)_, the cold crystallization temperatures (T_cc)_, and the heat of fusion (ΔH_f) values of PBN/PEG copolymers decreased on increasing PEG contents or molecular weights. The thermal stabilities of the copolymers were unaffected by PEG content or molecular weight. Hydrophilicities as determined by contact angle and moisture content measurements were found to be significantly increased on increasing PEG contents and molecular weights. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2677–2683, 2006     

Synthesis and characterization of thermoplastic poly(ester–siloxane)s

Two series of thermoplastic poly(ester–siloxane)s, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) as the hard segment, were synthesized by two‐step catalyzed transesterification reactions in the melt. Incorporation of soft poly(dimethylsiloxane) segments into the copolyester backbone was accomplished in two different ways. The first series was prepared based on dimethyl terephthalate, 1,4‐butanediol and silanol‐terminated poly(dimethylsiloxane) (PDMS‐OH). For the second series, the PDMS‐OH was replaced by methyl diesters of carboxypropyl‐terminated poly(dimethylsiloxane)s. The syntheses were optimized in terms of both the concentration of catalyst, tetra‐n‐butyl‐titanate (Ti(OBu)₄), and stabilizer, N,N′‐diphenyl‐p‐phenylene‐diamine, as well as the reaction time. The reactions were followed by measuring the inherent viscosities of the reaction mixture. The molecular structures of the synthesized poly(ester–siloxane)s were verified by ¹H NMR spectroscopy, while their thermal properties were investigated using differential scanning calorimetry. © 2001 Society of Chemical Industry     

Synthesis and characterization of novel heat resistance poly(amide‐imide)s from N,N′‐[2,5‐bis(4‐aminobenzylidene) cyclopentanone] bistrimellitimide acid and various aromatic diamines

A new‐type of dicarboxylic acid was synthesized from the reaction of 2,5‐bis(4‐aminobenzylidene)cyclopentanone with trimellitic anhydride in a solution of glacial acetic acid/pyridine (Py) at refluxing temperature. Six novel heat resistance poly(amide‐imide)s (PAIs) with good inherent viscosities were synthesized, from the direct polycondensation reaction of N,N′‐[2,5‐bis(4‐aminobenzylidene)cyclopentanone]bistrimellitimide acid with several aromatic diamines, by two different methods such as direct polycondensation in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride (CaCl₂)/pyridine (Py) and direct polycondensation in a p‐toluene sulfonyl chloride (tosyl chloride, TsCl)/pyridine (Py)/N,N‐dimethylformamide (DMF) system. All of the above polymers were fully characterized by ¹H NMR, FTIR, elemental analysis, inherent viscosity, solubility tests, UV‐vis spectroscopy, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and derivative of thermaogravimetric (DTG). The resulted poly(amide‐imide)s (PAIs) have showed admirable good inherent viscosities, thermal stability, and solubility. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of poly(p‐phenylene)‐graft‐poly(ε‐caprolactone) copolymers by combined ring‐opening polymerization and cross‐coupling processes

2,5‐Dibromo‐1,4‐(dihydroxymethyl)benzene was used as initiator in ring‐opening polymerization of ε‐caprolactone in the presence of stannous octoate (Sn(Oct)₂) catalyst. The resulting poly(ε‐caprolactone) (PCL) macromonomer, with a central 2,5‐dibromo‐1,4‐diphenylene group, was used in combination with 1,4‐dibromo‐2,5‐dimethylbenzene for a Suzuki coupling in the presence of Pd(PPh₃)₄ as catalyst or using the system NiCl₂/bpy/PPh₃/Zn for a Yamamoto‐type polymerization. The poly(p‐phenylenes) (PPP) obtained, with PCL side chains, have solubility properties similar to those of the starting macromonomer, ie soluble in common organic solvents at room temperature. The new polymers were characterized by ¹H and ¹³C NMR and UV spectroscopy and also by GPC measurements. The thermal behaviour of the precursor PCL macromonomer and the final poly(p‐phenylene)‐graft‐poly(ε‐caprolactone) copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry analyses and compared. Copyright © 2004 Society of Chemical Industry