Synthesis,characterization, and thermal degradation mechanism of fast biodegradable PPSu/PCL copolymers

Poly(propylene succinate)/poly(ε‐caprolactone) (PPSu/PCL) 25/75, 50/50, and 75/25 w/w copolymers were prepared using a combination of polycondensation and ring opening polymerization. The randomness of copolymers was characterized using ¹H NMR and ¹³C NMR spectroscopy. From molecular weights and DSC measurements it was observed that the molecular weight decreased with increasing the wt % content of PPSu, while the copolymers containing 50 and 75 wt % PPSu were completely amorphous. Enzymatic hydrolysis revealed that biodegradation rate was much enhanced compared with that of neat PCL and increased by increasing the PPSu content. From TGA analysis it was also found that the PPSu/PCL copolymers had similar thermal decomposition behaviour with the pure polyesters and exhibited their maximum decomposition rates at temperatures 400–420 °C. Two different mechanisms, which follow each other, were used to adequately describe their decomposition kinetics. The first one corresponded to the first stage taking place at 280–365 °C, where small mass loss was recorded and activation energies ranged between 94 and 156 kJ/mol. The second one took place at 370–460 °C and corresponded to the stage where the main polyester mass was decomposed. The activation energies for this stage ranged between 200 and 240 kJ/mol. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5076–5090, 2007     

Synthesis, characterization, and thermal properties of diacrylic/divinylbenzene copolymers

In this article, synthesis, characterization, and thermal properties of diacrylic/divinylbenzene copolymers based on the new aromatic tetrafunctional acrylate monomers are presented. The new monomers were generated by treatment of epoxides derived from various aromatic diols: naphthalene-2,3-diol (NAF), biphenyl-4,4′-diol (BIF), bis(4-hydroxyphenyl)methanone (BEP) or 4,4′-thiodiphenol (BES), and epichlorohydrin with acrylic acid. The addition reaction was carried out by a ratio of 0.5 mol of suitable epoxy derivative and 1 mol of acrylic acid in the presence of 0.7 wt% of triethylbenzylammonia chloride (TEBAC) as a catalyst and 0.045 wt% of hydroquinone as a polymerization inhibitor. The chemical structure of the prepared acrylate monomers was confirmed by ¹³C NMR and GC MS spectra. The emulsion–suspension polymerization of acrylate monomers with divinylbenzene (DVB) in the presence of pore-forming diluents (toluene + decan-1-ol) allowed obtaining microspheres containing pendant functional groups (hydroxyl groups). This process was carried out at constant mol ratio of acrylate monomers: DVB (1:1), and constant volume ratio of pore-forming diluents to monomers (1:1). The different concentrations of toluene in the mixture with decan-1-ol were used for qualifying the effect of the diluents on the microsphere characteristics. The influence of synthesis’s parameters on the properties of copolymer beads, e.g., pore size and surface area by BET method, the surface texture by AFM, swelling behavior in polar and non-polar solvents as well as thermal stability by differential scanning calorimetry (DSC), and thermogravimetric analysis (TG) was studied and discussed.     

Synthesis and characterization of biodegradable homopolymers and block copolymers based on adipic anhydride

Homopolymers of adipic anhydride (AA) and block copolymers of ϵ-caprolactone (ϵ-CL) and AA have been synthesized with aluminum triisopropoxide as an initiator. Homopolymerization was studied at 20°C in toluene and methylene chloride (CH₂Cl₂). The end-group analysis agrees with a coordination insertion mechanism based on the acyl-oxygen cleavage of the AA ring. Living poly(ϵ-caprolactone) (PCL) chains are very efficient macro-initiators for the polymerization of AA, with formation of diblock copolymers of a narrow molecular weight distribution. At our best knowledge, low molecular weight ω-aluminum alkoxide PCL macroinitiators (M_n < 1000) allow the first valuable synthesis of PAA with a molecular weight as high as 58,000 and a quite narrow polydispersity (M_w/M_n = 1.2). Size-exclusion chromatography (SEC) and ¹³C NMR confirm the blocky structure of the copolymers, in agreement with DSC that shows two melting endotherms and two glass transitions characteristic of the crystalline and amorphous phases of PCL and PAA, respectively. Block copolymers of ϵ-CL and AA are also sensitive to hydrolysis, which makes them possible candidates for biomedical applications. Initiation of the AA polymerization in bulk with aluminum triisopropoxide in the presence of various ligands is also discussed. © 1997 John Wiley & Sons, Inc.     

Synthesis and modification of new biodegradable copolymers: Serine/glycolic acid based copolymers

Serine/glycolic acid-based biodegradable polymers have been prepared by ring-opening homopolymerization of 3-(O-benzyl)-L -serinylmorpholine-2,5-dione, and ring-opening copolymerization of the morpholine-2,5-dione derivative and L -lactide/ϵ-caprolactone. The homopolymerization was carried out in the melt at 165°C for 3 min using stannous octanoate as the initiator and continued at lower reaction temperatures (130–150°C) for 48 h, using a molar ratio of monomer and initiator of 1000 yielded a polymer of M_n = 4000. The polymer prepared by homopolymerization of the morpholine-2,5-dione derivative was composed of alternating protected serine and glycolic acid residues. Random copolymers of serine and glycolic acid and L -lactic acid/ϵ-caprolactone were synthesized by copolymerization reaction of 3-(O-benzyl)-L -serinylmorpholine-2,5-dione and lactide or ϵ-caprolactone in the melt at 165°C for 3 min and further reaction at 130°C using stannous octanoate as an initiator. The polymers were deprotected and functionalized through the side chain hydroxyl group of serine residues with an acrylate moiety for applications in injectable drug delivery, cell encapsulation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1901–1907, 1997     

Synthesis and characterization of biodegradable palm palmitic acid based bioplastic

This study involves the quantitative analysis of high free fatty acid crude palm oil, the separation of palmitic acid and synthesis of palm palmitic acid-based bioplastic. Synthesis of dimethyl 2-tetradecylmalonate (DMTDM) using methyl palmitate (MP) with sodium hydride (NaH) in the presence of reactive solvent of dimethyl carbonate (DMC) was carried out. The reaction conditions comprise at a mole ratio of MP: DMC: NaH: dimethylformamide (DMF) (0.1:2:0.25:1) at 60 °C for 14 h with 88.3 ± 1.4% yield. FTIR spectra of DMTDM showed the ester carbonyl group at 1740 cm^–1. The polymerization of DMTDM with 1,6-hexandiol or 1,12-dodecandiol was carried out using titanium (IV) isopropoxide Ti(OiPr)₄ as the catalyst and reaction time of 24 h. The results showed that the poly(dodecyl 2-tetradecylmalonte) (PDTDM) exhibited good thermal properties compared to poly(hexyl 2-tetradecylmalonte) (PHTDM). The increase of the chain length of diol in PDTDM improved the thermal properties of polyester with glass transition, T_g of 13 ºC and melting point of 51 ºC with a molecular weight of 12508 Da and polydispersity index (PDI) of 1.4. In general, the synthetic polyesters can be used as internalplasticizer in bio-based industry.     

Synthesis,characterization and in vitro degradation of biodegradable polyesteramide based on lactic acid

A new type of biodegradable polyesteramide P(LA/AU) based on lactic acid and aminoundecanoic acid was synthesized by the melt polycondensation method. The copolymers obtained were characterized by FTIR, ¹H-NMR, DSC, and XRD. The in vitro degradation behavior of the copolymers was studied using weighing, ¹H-NMR, FTIR, DSC, and SEM. With the increase in aminoundecanoic acid units, the melting temperature and crystallinity increased, but the water absorption and degradation rate decreased accordingly. During degradation in vitro, the ester moiety decreased due to ester cleavage along the macromolecular main chain. As degradation proceeded, the melting temperature and crystallinity increased at first, then started to decrease because the crystalline phase was destroyed.     

Synthesis,characterization, thermal stability and antibacterial activity of coumarin based methacrylate copolymers

Monomer of 7-methacryloyloxy-4-methylcoumarin(MAOMC) was synthesized and characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy. Copolymers of MAOMC with butoxyethylmethacrylate(BOEMA) at different feed compositions were prepared by free radical solution polymerization at(70 ± 1) °C in ethylmethylketone(EMK) using benzyl peroxide(BPO) as an initiator. The copolymers were characterized by FTIR and 1H-NMR spectroscopy. Thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC) of the copolymers showed moderate thermal stability and higher Tg values. Gel permeation chromatography(GPC) was used to find out the molecular weights of the different copolymers. Antibacterial activities of the copolymers were also investigated against the selected pathogenic bacteria's. The antibacterial activity of the copolymer increases as the MAOMC content increases in the copolymer. This shows that coumarin moiety plays a very important role in the antibacterial activity.     

Optical, dynamic, and electro-optical properties of poly(N-acryloyl-11-aminoundecanoic acid) in solutions

The optical, electro-optical, and dynamic characteristics of poly(N-acryloyl-11-aminoundecanoic acid) in organic solvents and of the sodium salt of its monomer in water were studied via the methods of flow birefringence, equilibrium and nonequilibrium electric birefringence, and dynamic light scattering. It is shown that, in aqueous solutions, the monomer forms coarse particles of both symmetric and asymmetric shapes. The linear dimensions of these particles are estimated from the data of translational and rotational diffusion. Polymer macromolecules in organic solvents feature negative anisotropy of optical polarizability. Contributions of optical microform and macroform effects to the observed flow birefringence are analyzed in detail. The intrinsic optical anisotropy of the monomer unit of the polymer, which correlates well with the corresponding values for comb-shaped polymers of a similar structure, is estimated. It is shown that polymer molecules lack marked intrinsic permanent macromolecular dipoles and that electric birefringence in their solutions is associated with macroscopic induced dipole moments that appear during orientation of the dipole moments of polar groups in side chains of the polymer under application of an electric field.     

Synthesis and characterization of potentially biodegradable thermotropic polyesters based on p-hydroxybenzoic acid and glycolic acid

The synthesis of novel thermotropic liquid crystalline copolyesters derived from aliphatic hydroxy acid (glycolic acid, GA) and aromatic hydroxy acid (p-hydroxybenzoic acid, PHBA) via a melt-copolycondensation process in the presence of various catalysts was explored. The following three possible routes were checked: PHBA and GA in different feed ratios with or without a catalyst; PHBA and GA in different feed ratios with or without a catalyst in the presence of acetic anhydride as a condensation agent; and different PHBA derivatives were used to examine the reactivity of aromatic hydroxy acid. The copolycondensability, chemical structure, liquid crystallinity, textures and morphology, phase transition behaviors and thermal stability, and solubility were investigated by FTIR, NMR, DSC, TGA, and polarized-light microscope. It has been found that only the 60–70 mol % PHBA-containing copolyesters could exhibit a nematic liquid crystallinity. The as-prepared polymers were brittle due to relatively lower molecular weights. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of copolymers based on benzothiadizole-thiophene-phenylenevinylene

<正>Two novel copolymers based on benzothiadizole-thiophene-phenylenevinylene have been synthesized through palladium catalyzed triple-bond polycondensation method.The copolymers exhibit good solubility in common organic solvents such as CHCl_3,CH_2Cl_2 and THF.The structures and properties of the two copolymers are characterized by FT-IR, ~1H-NMR,UV-Vis absorbance(Abs),gel permeation chromatography(GPC),thermal gravimetric analysis and cyclic voltammetry(CV).The copolymers of P_1 and P_2 show absorption spectra with maximum peak at 532 nm and 573 nm in solution,respectively.Compare to their monomers M_1 and M_2,the absorption peaks of P_1 and P_2 were red-shifted by 34 nm and 54 nm respectively.Thermal gravimetric analysis demonstrated that the polymers were stable and little weight loss was observed below 300℃.Cyclic voltammetry experiments showed that the band gaps of the copolymers were 1.81 eV and 1.62 eV,respectively,suggesting their potential for applications as organic solar cell materials.     

Synthesis,characterization, and properties of block and bigraft copolymers

The syntheses of poly(styrene-b-isobutylene), poly[(ethylene-co-propylene-co-1,4-hexadiene)-g-styrene-g-α-methylstyrene], and poly[(ethylene-co-propylene-co-1,4-hexadiene)-g-styrene-g-isobutylene] have been accomplished by using the principle of selective sequential initiation. This method makes use of the large differences in initiation rates that exist between labile organic chlorides and bromides when these halides interact with alkylaluminum compounds. Synthesis conditions have been worked out which allow composition control. These new AB blocks and bigrafts exhibit unusual mechanical and solubility properties, some of which will be described. For example, the Nordel-g-PSt-g-PIB bigraft exhibits only one low temperature transition (DSC, Rheovibron), suggesting an intimate aggregation of Nordel and polyisobutylene phases.     

Synthesis and thermal properties of crosslinkable phosphazene copolymers

Polyphosphazenes of formula [NP(OC₆H₄CN)_x(OCH₂CF₃)_2?x] (x = 0.04–2) were prepared. The copolymers were crosslinked via cyclotrimerization of the nitrilic function, using acid catalysts (chlorosulfonic acid, aluminum chloride) at elevated temperatures. The thermal properties of the crosslinked cyclomatrix polymer were compared to the linear polymer by thermogravimetric analysis and differential scanning calorimetry. When the 4-cyanophenoxy-2,2,2-trifluoroethoxy ratios were less than 0.2, the crosslinked polymers were soluble in polar organic solvents.     

Carbohydrate‐based amphiphilic diblock copolymers: Synthesis,characterization, and aqueous properties

Amphiphilic poly(ε‐caprolactone)‐b‐poly[(methacrylate‐graft‐poly(ethylene oxide))‐co‐6‐O‐methacryloyl‐D ‐galactopyranose] (PCL‐b‐P(MAPEO‐co‐GaMa)) with various compositions and molecular weights were synthesized via a controlled four‐step strategy. The first step involves the synthesis of functionalized poly(ε‐caprolactone) macroinitiator by ring‐opening polymerization (ROP) of ε‐caprolactone (CL) as initiated by aluminum triisopropoxide (Al(OⁱPr)₃). After selective bromination of the hydroxyl end‐group of the resulting α‐isopropoxy, ω‐hydroxy poly(ε‐caprolactone) by using 2‐bromoisobutyryl bromide, the controlled radical copolymerization of α‐methoxy, ω‐methacrylate poly(ethylene oxide) (MAPEO) with 6‐O‐methacryloyl‐1,2;3,4‐di‐O‐isopropylidene‐D ‐galactopyranose (DIGaMa) was performed by atom transfer radical polymerization (ATRP) in THF at 60 °C using CuBr ligated with 1,1,4,7,10,10 hexamethyltriethylenetetramine (HMTETA) as catalytic complex. In the final step, isopropylidene protective functions were selectively removed using an aqueous formic acid solution leading to the expected amphiphilic graft copolymers. The molecular characterization of those copolymers was performed by ¹H NMR spectroscopy and gel permeation chromatography (GPC) analysis. The self‐assembly of the copolymers into micellar aggregates as well as the related critical micellization concentration (CMC) in aqueous media were determined by dynamic light scattering (DLS) and fluorescence spectroscopy, respectively. In parallel, the morphology of the solid deposits of micellar aggregates was examined with atomic force microscopy (AFM). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3662–3672, 2008     

Synthesis and characterization of biodegradable and weather-durable PET/PEG/NDC copolymers

Polyethylene terephthalate/poly(ethylene glycol)/2, 6-naphthalene dicarboxylate (PET/PEG/NDC) copolymers were synthesized and characterized. The results demonstrated that T _g dramatically decreased—by approximately 20?°C—when 8?wt.% PEG was added to neat PET. However, T _g slightly increased—by around 6?°C—from the reduced value, when a third ingredient, NDC, was incorporated. The melting temperature T _m and fusion enthalpy △H _m decreased when the 8?wt.% PEG was copolymerized. Further incorporation of NDC into the PET/8?% PEG copolymer, after a small initial increase in T _m and △H _m for PET/8?% PEG/2.3?% NDC, caused substantially reduce in both properties for PET/8?% PEG/9.2?% NDC. A mechanical test revealed that PET/8?% PEG/NDC copolymers maintained high mechanical integrity until degradation, verifying that the inclusion of NDC enhances the weatherability of PET/PEG copolymer. The rheological Cole–Cole plots indicated the occurrence of phase separation in PET/PEG melt, but the incorporation of NDC suppressed this incompatibility. The biodegradation results indicated that the degradation comprised two stages—a period of rapid degradation, which was associated with the hydrolysis of PEG segments, and a period of slow degradation, which was caused by erosion of the short aliphatic segments by the microbes.     

Synthesis, characterization, degradation of biodegradable castor oil based polyesters

A new family of castor oil based biodegradable polyesters was synthesized by catalyst free melt condensation reaction between two different diacids and castor oil with d-mannitol. The polymers synthesized were characterized by NMR spectroscopy, FT-IR and the thermal properties were analysed by DSC. The results of DSC show that the polymer is rubbery in physiological conditions. The contact angle measurement and hydration test results indicate that the surface of the polymer is hydrophilic. The mechanical properties, evaluated in the tensile mode, shows that the polymer has characteristics of a soft material. In vitro degradation of polymer in PBS solution carried out at physiological conditions indicates that the degradation goes to completion within 21 days and it was also found that the rate of degradation can be tuned by varying the curing conditions.     

Synthesis, characterization and biodegradable studies of 1,3-propanediol based polyesters

A series of biodegradable polyesters were synthesized from dicarboxylic acids and 1,3-propanediol catalyzed by transestrification polycondensation reaction in the bulk. The structure, average molecular weights and physical properties of the resulting aliphatic polyesters were characterized by ¹H NMR, FT-IR, solution viscosity, GPC, DSC and TGA. Homopolyesters show higher degree of crystallinity, melting and thermal stability in comparison to copolyesters. The biodegradability of the polyesters was determined by monitoring the normalized weight loss of polyester films with time in phosphate buffer (pH 7.2) without and with Rhizopus delemar lipase at 37 °C. The rate of enzymatic degradation of homopolyesters follows the path PPSu > PPAd > PPSe. PPSe did not show significant weight loss in presence of enzyme which may be due to its highest degree of crystallinity and melting point compared to the PPSu, PPAd and copolyesters. In the soil burial degradation polyester sample showed severe surface degradation by the attack of microorganism.     

Novel methacrylate copolymers with fluorine containing: Synthesis, characterization, reactivity ratios, thermal properties and biological activity

New methacrylate based monomers 2-(4-benzoylphenoxy)-2-oxoethyl-2-methylacrylate (BOEMA), 2-(4-acetylphenoxy)-2-oxoethyl-2-methylacrylate (AOEMA), and 2-[(4-fluorophenyl)amino]-2-oxoethyl-2-methylacrylate (FPAMA), were synthesized first time. The free-radical-initiated copolymerization of AOEMA and BOEMA with FPAMA were carried out in 1,4-dioxane solution at 65 °C using 2,2′-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomers and copolymers were characterized by FTIR, ¹H NMR and ¹³C NMR spectral studies. The copolymer compositions were evaluated by nitrogen content in polymers. The reactivity ratios of the monomers were determined by the application of Fineman-Ross and Kelen-Tudos methods. The analysis of reactivity ratios revealed that BOEMA and AOEMA are less reactive than FPAMA, and copolymers formed are statistically in nature. The molecular weights ( and ) and polydispersity index of the polymers were determined using gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of FPAMA in the copolymers. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of FPAMA in the copolymers. The prepared homo and copolymers were tested for their antimicrobial activity against bacteria, fungi and yeast.     

Synthesis, characterization and thermal properties of metaloquinolate-containing polymers

The monomer, 5-methyl(2-methacryloylethyloxy)-8-quinolinol(HEMA-CH₂-Hq), which possesses both double bond and 8-hydroxyquinoline groups, was synthesized from 2-hydroxyethyl methacrylate (HEMA) and 5-chloromethyl-8-quinolinol hydrochloride. The model polymer with 8-hydroxyquinoline ligands was obtained by free-radical copolymerization with styrene. So metaloquinolate (AlQ₃, ZnQ₂)-containing polymers are prepared by coordinating reaction with di(8-hydroxyquinoline) aluminum(AlQ₂) chelates or mono(8-hydroxyquinoline) zinc(ZnQ) chelates without cross-linking. Both polymer and polymer complexes were analyzed by FT-IR, UV-vis, DSC, TGA and photoluminescence spectroscopies. They are soluble in common solvents and easy to form films. The use of AlQ₂ and ZnQ avoided the cross-linking caused by the AlQ₃, ZnQ₂ formation between different polymer chains. High glass transition temperature, good thermal stability, and strong yellow-green fluorescence were observed for the prepared polymers. These polymers were expected to have the potential application in yellow-green OLEDs.     

Synthesis,characterization, and thermal properties of ladderlike polyepoxysiloxanes

Starting from trichlorosilanes and using 1,4‐phenylenediamine as a template, we have synthesized some ladderlike poly(glycidyl‐co‐alkyl/aryl)siloxanes (polyepoxysiloxanes or polyepoxies for short). The structures of copolymers were confirmed through IR, ¹H NMR, elemental analyses, and gel permeation chromatography. Curing behaviors of these polyepoxies in the absence and presence of a curing agent have been studied with DSC. It was shown that these epoxies could be cured without any curing agent. Copolymers having aromatic groups showed higher curing reactivity than those having alkyl groups. The experimental results also demonstrate that the curing reaction occurred solely via epoxy functionality, not via the condensation reaction of the hydroxy groups located at the end of polymer main chains. The thermal stability of the cured polymers was examined by thermogravimetric analysis. The results confirm that polyepoxies with aromatic groups had better thermal stability than those with alkyl groups. It was also found that polyepoxies cured with a diamine have a higher thermal stability than those cured in the absence of a curing agent. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2215–2222, 2001