Synthesis and biological activity of medium range molecular weight polymers containing exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid (ETCA), was prepared by reaction of maleimidocaproic acid and furan. The homopolymer of ETCA and its copolymers with acrylic acid (AA) or with vinyl acetate (VAc) were obtained by photopolymerizations using 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C. The synthesized ETCA and its polymers were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The apparent average molecular weights and polydispersity indices determined by gel permeation chromatography (GPC) were as follows: M_n = 9600 g mol^?1, M_w = 9800 g mol^?1, M_w/M_n = 1.1 for poly(ETCA); M_n = 14 300 g mol^?1, M_w = 16 200 g mol^?1, M_w/M_n = 1.2 for poly(ETCA‐co‐AA); M_n = 17 900 g mol^?1, M_w = 18 300 g mol^?1, M_w/M_n = 1.1 for poly(ETCA‐co‐VAc). The in vitro cytotoxicity of the synthesized compounds against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines decreased in the following order: 5‐fluorouracil (5‐FU) ≥ ETCA > polymers. The in vivo antitumour activity of the polymers against Balb/C mice bearing sarcoma 180 tumour cells was greater than that of 5‐FU at all doses tested. © 2001 Society of Chemical Industry     

Synthesis and biological activity of phthalimide‐based polymers containing 5‐fluorouracil

The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 8900 g mol^?1, M_w = 13 300 g mol^?1, M_w/M_n = 1.5 for poly(ETPFU); M_n = 13 500 g mol^?1, M_w = 16 600 g mol^?1, M_w/M_n = 1.2 for poly(ETPFU‐co‐AA); M_n = 8300 g mol^?1, M_w = 11 600 g mol^?1, M_w/M_n = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg^?1). © 2002 Society of Chemical Industry     

Synthesis and antitumour activity of medium molecular weight phthalimide polymers of camptothecin

Attachment of anticancer agents to polymers has been demonstrated to improve their therapeutic profiles. A new monomer containing camptothecin, 5‐norbonene‐endo‐2,3‐dicarboxylimidoundecanoyl‐camptothecin (NDUCPT) and its homopolymer and copolymer with acrylic acid (AA) were synthesized and spectroscopically characterized. The NDUCPT content in poly(NDUCPT‐co‐AA) obtained by elemental analysis was 51%. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 12 100, M_w = 23 400 g mol^?1, M_w/M_n = 1.93 for poly(NDUCPT), M_n = 15 400, M_w = 28 300 g mol^?1, M_w/M_n = 1.83 for poly(NDUCPT‐co‐AA). The IC₅₀ value of NDUCPT and its polymers against U937 cancer cells was larger than that of CPT. The in vivo antitumour activity of all polymers in Balb/C mice bearing the sarcoma 180 tumour cell line was greater than that of CPT at a dose of 100 mg kg^?1. Copyright © 2003 Society of Chemical Industry     

Synthesis,antitumour and DNA replication activities of polymers containing vinyl‐(5‐fluorouracil)‐ethanoate

A new monomer, vinyl‐(5‐fluorouracil)‐ethanoate (VFUE), was synthesized by reaction of 5‐fluorouracil (5‐FU) and vinyl iodoacetate. The homopolymer of VFUE and its copolymers with acrylic acid (A, A) and maleic anhydride (MAH) were prepared by photopolymerization. The synthesized VFUE and polymers were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The contents of VFUE unit in poly(VFUE‐co‐AA) and poly(VFUE‐co‐MAH) were 21 mol% and 16 mol%, respectively. The number average molecular weights of the polymers determined by gel permeation chromatography were in the range 9600–17900 g mol^?1. The in vitro cytotoxicities of the samples against a normal cell line decreased as follows: 5‐FU > VFUE > poly(VFUE) > poly(VFUE‐co‐AA) > poly(VFUE‐co‐MAH). The in vivo antitumour activities of the polymers against Balb/C mice bearing the sarcoma 180 tumour cells were greater than those of 5‐FU at all concentrations. The inhibition of simian virus 40 DNA replication by the samples was much greater than that of the control. © 2002 Society of Chemical Industry     

Synthesis and antitumour and antiangiogenesis activity of polymers containing methacryloyl‐2‐oxy‐1,2,3‐propane tricarboxylic acid

A new monomer, methacryloyl‐2‐oxy‐1,2,3‐propane tricarboxylic acid (MTCA), was synthesized from citric acid and methacrylic anhydride. Poly(methacryloyl‐2‐oxy‐1,2,3‐propane tricarboxylic acid) and poly(methacryloyl‐2‐oxy‐1,2,3‐propane tricarboxylic acid)‐co‐(maleic anhydride) were prepared by radical polymerizations. Terpoly(methacryloyl‐2‐oxy‐1,2,3‐propane tricarboxylic acid–maleic anhydride–furan) was obtained by in situ terpolymerization of MTCA and exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalic anhydride. The synthesized samples were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The number‐average molecular weights of the fractionated polymers determined by GPC were in the range 14 900–16 600 and polydispersity indices were less than 1.14. The in vitro IC₅₀ values of the monomer and polymers against cancer and normal cell lines were much higher than those of 5‐fluorouracil (5‐FU). The in vivo antitumour activities of the synthesized samples at a dosage of 0.8 mg kg⁻¹ against mice bearing the sarcoma 180 tumour cell line decreased in the order terpoly(MTCA‐MAH‐FUR) > poly(MTCA‐co‐MAH) > poly(MTCA) > MTCA > 5‐FU. The synthesized samples inhibited DNA replication and angiogenetic activity more than did 5‐FU. © 2001 Society of Chemical Industry     

Synthesis and characterization of high molecular weight metaloquinolate‐containing polymers

In this article, a new method to synthesize novel metaloquinolate (AlQ₃, ZnQ₂)‐containing polymers is reported. A model polymer with 8‐hydroxyquinoline ligands can be obtained by free‐radical copolymerization with methyl methacrylate (MMA), then 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 crosslinking. The structures of products are confirmed by NMR, FTIR, ultraviolet‐visible, elementary analysis, photoluminescence spectrum, and gel permeation chromatography analysis. They are soluble in common solvents and suitable to form films. The use of AlQ₂ and ZnQ avoided the crosslinking caused by the AlQ₃, ZnQ₂ formation between different polymer chains. Different from the traditional small organic molecules in organic light‐emitting diodes (OLEDs) fabrication, the polymer can be processed by spin coating without phase separation. Compared to the PMMA or MMA‐co‐HEMA‐CH₂‐Hq, the T_g of the metaloquinolate‐containing polymers was much higher. It should be of interest for OLED applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1945–1952, 2006     

Syntheses and biological activities of polymers containing methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid or 5‐fluorouracil

A series of novel copolymers, poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalic acid) [poly(MTCA‐co‐ETAc)], poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐hydrogenethyl‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalate) [poly(MTCA‐co‐HEET)], and poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐α‐ethoxy‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthaloyl‐5‐fluorouracil) [poly(MTCA‐co‐EETFU)], were prepared from corresponding monomers by photopolymerizations at 25°C for 48 h. The polymers were identified by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopies. The number‐average molecular weights of the fractionated polymers determined by GPC were in the range from 9400 to 14,900 and polydispersity indices were 1.2–1.4. The in vitro IC₅₀ values of polymers against mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as cancer cell lines and mouse liver cells (AC2F) as a normal cell line were much higher compared to that of 5‐fluorouracil (5‐FU). The in vivo antitumor activities of monomers and polymers against mice bearing sarcoma 180 tumor cell line were better than those of 5‐FU. The inhibition of DNA replication and antiangiogenesis activities of MTCA and copolymers were better compared to those of 5‐FU. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 57–64, 2004     

Preparation and drug release behaviors of 5‐fluorouracil loaded poly(glycolide‐co‐lactide‐co‐caprolactone) nanoparticles

5‐Fluorouracil (5‐Fu) loaded poly(glycolide‐co‐lactide‐co‐caprolactone) (PGLC) nanoparticles were prepared by modified spontaneous emulsification solvent diffusion method (modified‐SESD method) and characterized by dynamic light scattering, scanning electron microscopy and ¹H NMR determination. It was found that the obtained nanoparticles showed near spherical shape and was controllable with the radius range of 30–100 nm. Compared with the nanoparticles prepared by polylactide and poly (lactide‐co‐glycolide) (PLGA) under the similar preparation condition, yield of PGLC nanoparticles was the highest, which reached to about 100%. On the other hand, drug entrapment efficiency of PGLC nanoparticles was also higher than that of PLGA and PLLA nanoparticles. 5‐Fu release behavior of PGLC nanoparticles in vitro showed that 5‐Fu release of PGLC nanoparticles showed a near zero‐order release profile, and 5‐Fu release rate of PGLC nanoparticles was faster than that of PLLA and PLGA nanoparticles. According to degradation behavior of PGLC nanoparticles, it could be proposed that the kinetic of degradation controlled release played an important role in the release process of PGLC nanoparticles. It revealed that the PGLC nanoparticles could be a promising drug carrier. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Biodegradable polymers based on renewable resources. V. Synthesis and biodegradation behavior of poly(ester amide)s composed of 1,4:3,6‐dianhydro‐D‐glucitol, α‐amino acid,and aliphatic dicarboxylic acid units

A series of poly(ester amide)s were synthesized by solution polycondensations of various combinations of p‐toluenesulfonic acid salts of O,O′‐bis(α‐aminoacyl)‐1,4:3,6‐dianhydro‐D ‐glucitol and bis(p‐nitrophenyl) esters of aliphatic dicarboxylic acids with the methylene chain lengths of 4–10. The p‐toluenesulfonic acid salts were obtained by the reactions of 1,4:3,6‐dianhydro‐D ‐glucitol with alanine, glycine, and glycylglycine, respectively, in the presence of p‐toluenesulfonic acid. The polycondensations were carried out in N‐methylpyrrolidone at 40°C in the presence of triethylamine, giving poly(ester amide)s having number‐average molecular weights up to 3.8 × 10⁴. Their structures were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. Most of these poly(ester amide)s are amorphous, except those containing sebacic acid and glycine or glycylglycine units, which are semicrystalline. All these poly(ester amide)s are soluble in a variety of polar solvents such as dimethyl sulfoxide, N,N‐dimethylformamide, 2,2,2‐trifluoroethanol, m‐cresol, pyridine, and trifluoroacetic acid. Soil burial degradation tests, BOD measurements in an activated sludge, and enzymatic degradation tests using Porcine pancreas lipase and papain indicated that these poly(ester amide)s are biodegradable, and that their biodegradability markedly depends on the molecular structure. The poly(ester amide)s were, in general, degraded more slowly than the corresponding polyesters having the same aliphatic dicarboxylic acid units, both in composted soil and in an activated sludge. In the enzymatic degradation, some poly(ester amide)s containing dicarboxylic acid components with shorter methylene chain lengths were degraded more readily than the corresponding polyesters with Porcine pancreas lipase, whereas most of the poly(ester amide)s were degraded more rapidly than the corresponding polyesters with papain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2721–2734, 2001     

Syntheses,antitumour activities and antiangiogenesis of 1,2,3‐tris(ethoxycarbonyl)‐2‐propyl acrylate and its polymers

A new monomer, 1,2,3‐tris(ethoxycarbonyl)‐2‐propyl acrylate (TPA), was synthesized by reaction of acryloyl chloride and triethyl citrate. The homopolymer of TPA and its copolymers with acrylic acid (AA), vinyl acetate (VAc) and maleic anhydride (MAH) were prepared by polymerization using lauroyl peroxide (LPO) at 70 °C for 24 h. The structures of TPA and its polymers were identified by FTIR, ¹H NMR, ¹³C NMR spectroscopies, and elemental analysis. The number average molecular weights and polydispersity indices of the synthesized polymers determined by GPC were in the range 4200–23 000 g mol^?1 and 1.1–2.1, respectively. The IC₅₀ values of the synthesized samples against cancer cell lines were greater than those of 5‐fluorouracil (5‐FU). The percentage inhibition values of SV40 DNA replication were 82.2 for TPA, 34.3 for poly (TPA), 81.9 for poly(TPA‐co‐AA), 82.0 for poly(TPA‐co‐VAc), 35.6 for poly(TPA‐co‐MAH) and 12.7 for 5‐FU. The inhibitions of SV40 DNA replication and antiangiogenesis for the synthesized TPA and its polymers are much greater than those of the control. © 2001 Society of Chemical Industry     

Synthesis of functionalizable and biodegradable polymers via ring‐opening polymerization of 5‐benzyloxy‐trimethylene carbonate and ε‐caprolactone

The biomedical applications of poly(ε‐caprolactone) (PCL) were limited for its high hydrophobicity and crystallinity. In this study, we copolymerized CL with amorphous 5‐hydroxyl‐trimethylene carbonate (HTMC) to solve the problem. The 5‐benzyloxy‐trimethylene carbonate (BTMC) was synthesized to copolymerize with CL, then hydrogenolyzed to obtain hydroxyl pendant groups. A serial of copolymers with different BTMC molar ratio were synthesized and their chemical structures and thermal properties were thoroughly studied with NMR, FT‐IR, GPC, XRD, DSC, and TGA. Finally we examined the water contact angle of the copolymers. DSC and XRD results showed that the PCL segments in the copolymers crystallized below 16.8%. BTMC molar content and the crystallinity of the copolymers increased after hydrolysis. With the introduced hydroxyl pendant groups, the deprotected copolymers improved their hydrophilic property significantly, and the copolymer with 9.3% HTMC molar content had static water contact angle as low as 36.5°. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hydrogen‐bonding interaction between poly(ε‐caprolactone) and low‐molecular‐weight amino compounds

The specific interactions between several low‐molecular‐weight diamino compounds and poly(ε‐caprolactone) (PCL) have been investigated by FT‐IR. It was found that PCL and 3,3′‐diaminodiphenylmethane (3,3′‐DADPM) interact through strong intermolecular hydrogen bonds in the blend. Thermal and mechanical properties of PCL/3,3′‐DADPM blends were investigated by DSC and tensile measurements, respectively. The glass transition temperature of the blend increases while both the melting point and the elongation‐at‐break of the blend decrease with the increase of 3,3′‐DADPM content. Besides 3,3′‐DADPM, several other low‐molecular‐weight compounds containing two amino groups, such as o‐phenylenediamine or 1,6‐diaminohexane, were also added into PCL and the corresponding blend systems were investigated by FT‐IR and DSC. The effect of the chemical structure of the additives on the properties of PCL is discussed. © 2001 Society of Chemical Industry     

Preparation and characterizaton of poly(dimethyl amino ethyl methacrylate) modified poly(vinyl alcohol) membrane by UV radiation for the permeation of 5‐fluorouracil

Poly(vinyl alcohol) was modified by UV radiation with dimethyl amino ethyl methacrylate (DMAEMA) monomer to get poly(dimethyl amino ethyl methacrylate) modified poly(vinyl alcohol) (PVADMAEMA) membrane. The PVADMAEMA membranes were characterized by Fourier transform infrared spectroscopy. The tensile strength and elongation of PVADMAEMA membranes were measured by Universal Testing Machine. The results of X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) showed that (1) the crystalline area in PVADMAEMA decreased with increasing the content of poly(dimethyl amino ethyl methacrylate) in the membrane. (2) Only one glass transition temperature (T_g) was found for the various PVADMAEMA membranes. It means that poly(dimethyl amino ethyl methacrylate) and PVA are compatible in PVADMAEMA membrane. (3)The T_g of the membrane is reduced with increasing the content of poly(dimethyl amino ethyl methacrylate) in the membrane. The water content on the PVADMAEMA membranes was determined. It was found that the water content on the PVADMAEMA membrane increased with increasing the content of poly(dimethyl amino ethyl methacrylate). The changes of properties enhanced the permeability of 5‐Fluorouracil (5‐Fu) through the PVADMAEMA membranes. A linear relationship between the permeability and the weight percent of poly(dimethyl amino ethyl methacrylate) in the PVADMAEMA membrane is found. It is expressed as P (cm/s) = (9.6 ± 0.4) × 10^?5 + (8.8 ± 0.6) × 10^?5 W _x , where P is the permeability of 5‐Fu through the membrane and W_x is the weight percent of poly(dimethyl amino ethyl methacrylate) in the PVADMAEMA membrane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Temperature sensitive semi‐IPN microspheres from sodium alginate and N‐isopropylacrylamide for controlled release of 5‐fluorouracil

Semi‐interpenetrating network (IPN) of sodium alginate (NaAlg) and N‐isopropylacrylamide (NIPAAm) microspheres were prepared by water‐in‐oil (w/o) emulsification method. The microspheres were encapsulated with 5‐fluorouracil (5‐FU) and release patterns carried in 7.4 pH at temperatures of 25 and 37°C. The semi‐IPN microspheres were characterized by Fourier transform infrared spectroscopy (FTIR). Differential scanning calorimetry (DSC) and scanning electron microscopic studies were done on the drug‐loaded microspheres to confirm the polymorphism of 5‐FU and surface morphology of microspheres. These results indicated the molecular level dispersion of 5‐FU in the semi‐IPN microspheres. Particle size and size distribution were studied by laser light diffraction technique. Microspheres exhibited release of 5‐FU up to 12 h. The swelling studies were carried in 1.2 and 7.4 pH buffer media at 25 and 37°C. Drug release from NaAlg‐NIPAAm semi‐IPN microspheres at 25 and 37°C confirmed the thermosensitive nature by in vitro dissolution. The micro domains have released in a controlled manner due the presence of NIPAAm in the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate

The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y³⁺, and taking Yb³⁺ and Y³⁺ as examples, RE³⁺ is extracted as RE(OH)A₂.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (?17.06 kJ mol^?1), enthalpy change ΔH (?35.08 kJ mol^?1) and entropy change ΔS (?60.47 J K^?1 mol^?1) for Y³⁺ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry     

Synthesis,characterization, and antitumor activity of poly(maleic anhydride‐co‐vinyl acetate‐co‐acrylic acid)

The ternary copolymerization of maleic anhydride (MA), vinyl acetate (VA), and acrylic acid (AA) [P(MA‐co‐VA‐co‐AA)], which is considered to be an acceptor–donor–acceptor system, was carried out in 1,4‐dioxane with benzoyl peroxide as an initiator at 70°C under a nitrogen atmosphere. Constants of complex formation for the monomer systems in the study were determined by UV–visible (hydrogen‐bonding complex) and ¹H‐NMR (charge transfer complex) methods, respectively. The results show that polymerization of the P(MA‐co‐VA‐co‐AA) system proceeds by an alternating terpolymerization mechanism. It is shown that the synthesized copolymers have typical polyelectrolyte behavior, ability for reversible hydrolysis–anhydrization reactions, and semicrystalline structures. In these cases, including radical polymerization, and formation of semicrystalline structures, the hydrogen‐bonding effect plays a significant role. The in vitro cytotoxicities of the synthesized terpolymer and alternating copolymer were evaluated using Raji cells (human Burkitt lymphoma cell line). The antitumor activities of prepared anion‐active copolymers were studied using methyl–thiazol–tetrazolium colorimetric assay and 50% of the cytotoxic dose of each copolymer and terpolymer were calculated. Hydrolyzed P(MA‐co‐VA‐co‐AA) and P(MA‐alt‐AA) copolymers have sufficiently high antitumor activity, which depends on the amount of hydrogen‐bonding carboxylic groups and their regular distribution in the side chain of functional macromolecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3425–3432, 2006     

Fast and efficient synthesis of high molecular weight poly(epsilon‐caprolactone) diols by microwave‐assisted polymer synthesis

Because of advantageous features such as shorter reaction times, greater yields, limited generation of by‐products and relatively easy and straightforward scale‐up, microwave‐assisted synthesis has become a very appealing tool in organic synthesis. Conversely, its implementation in the context of the synthesis of biomaterials for biopharmaceutical applications has been more limited. The present work reports on the fast and efficient microwave‐assisted synthesis of poly(ethylene glycol) (PEG)‐initiated poly(ε‐caprolactone) diols (PCL) by the ring‐opening polymerization (ROP) of ε‐caprolactone using stannous octanoate as catalyst. Since the PEG content in the synthesized copolymers was extremely low (0.2–1.9%), products were highly hydrophobic and displayed the intrinsic thermal properties of pure PCL. As opposed to the more time‐consuming conventional thermally‐driven synthesis that usually demands 2–3 h, the microwave technique resulted in intermediate to high molecular weight PEG‐PCL derivatives within 10–15 min. The influence of different parameters affecting the synthetic process, namely monomer‐to‐initiator ratio, reaction time, catalyst concentration and the presence, type, and concentration of solvent were thoroughly investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and molecular weight characterization of rubber seed oil‐modified alkyd resins

Alkyd resins of 40% (I), 50% (II), and 60% (III) oil length (OL) were prepared with rubber seed oil (RSO), phthalic anhydride (PA), and glycerol (GLY), employing the two‐stage alcoholysis method. Changes in the physical characteristics of the reaction medium were monitored by determination of the acid value and the number‐average molecular weight, M_n , of in‐process samples withdrawn at different stages of the reaction. The mode of variation of these properties denotes that the preparation of RSO alkyds is complex. Molecular weight averages and the molecular weight distribution (MWD) of the finished alkyds were determined by GPC, cryoscopy, and end‐group analysis. Molecular weight averages and the MWD vary with differences in the formulation, with sample II exhibiting the narrowest size distribution. Values of M_n with the corresponding polydispersities in brackets are 3234 (1.91), 1379 (1.56), and 3304 (2.56) for samples I, II, and III respectively. M_n values obtained by cryoscopy are comparable to those obtained by gel permeation chromatography (GPC), while end‐group analysis seems to grossly overestimate their molecular weights. Correlation of M_n and the MWD with the quality of the finished alkyds shows that the narrower the size distribution the better the quality of the alkyd. Properties such as the rate of drying and resistance of the alkyds are optimum at 50% OL. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2431–2438, 2001     

Influence of poly(ethylene glycol)‐containing additives on extrusion of ultrahigh molecular weight polyethylene/polypropylene blend

The influence of poly(ethylene glycol) (PEG)‐containing additives on the extrusion behavior of ultrahigh molecular weight polyethylene/polypropylene (UHMWPE/PP) blend was studied. It was found that the addition of small amounts of PEG to UHMWPE/PP blend resulted in significant reduction of die pressure and melt viscosity, and obvious increase of the flow rate at a given die pressure, while PEG/diatomite binary additives enhanced the improvement in the processability of UHMWPE/PP blend. When pure HDPE was extruded with the die through which UHMWPE/PP/PEG blend was previously extruded, the extrusion pressure of HDPE increased with the extrusion time gradually. This meant that PEG might migrate to the die wall surface and coat it in the extrusion of UHMWPE/PP/PEG blend. FTIR spectra and SEM micrographs of the UHMWPE/PP/PEG extrudates indicated that PEG located not only at the surface but also in the interior of the extrudates. So, the external lubrication at the die wall, combined with the internal lubrication to induce interphase slippage of the blend, was proposed to be responsible for the reduction of die pressure and viscosity. In addition, an ultrahigh molecular weight polysiloxane and a fluoropolymer processing aid were used as processing aids in the extrusion of UHMWPE/PP as control, and the results showed that only minor reduction effects in die pressure and melt viscosity were achieved at their suggested loading level. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1282–1288, 2006     

Syntheses and Biological Activities of Polymers Containing 3′-Azido-3′-deoxythymidine

The new monomer, 5′-O-methacryloyl-3′-azido-3′-deoxythymidine (MAZT), was synthesized by the reaction of methacryloyl chloride and 3′-azido-3′-deoxythymidine (AZT). Poly(MAZT) and copolymers of MAZT with vinyl acetate (VAc) and maleic anhydride (MAH) were synthesized by radical polymerizations. The synthesized MAZT and polymers were identified by ¹H nuclear magnetic resonance (NMR), ¹³C NMR, elemental analysis and gel permeation chromatography. The quantities of MAZT units in poly(MAZT-co-VAc) and poly(MAZT-co-MAH) were 45 and 27 mol%, respectively. The weight average molecular weights of the polymers synthesized were in the range from 8800 to 17600. The in vitro cytotoxicities of samples against K562 human leukaemia cell line at 100 μg ml^-1 decreased in the following order: poly(MAZT-co-MAH) > poly(MAZT-co-VAc) > poly(MAZT) > MAZT > AZT. The in vivo anti-tumour activities of the polymers synthesized against Balb/C mice bearing sarcoma 180 tumour cells were greater than those of 5-fluorouracil at all concentrations.