Random copolymerization of 2,2‐dimethyltri methylene carbonate and ε‐caprolactone using a rare‐earth tris(4‐tert‐butylphenolate)s as a single‐component initiator

Highly random copolymers of 2,2‐dimethyltrimethylene carbonate (DTC) and ε‐caprolactone (CL) were synthesized by single component rare‐earth tris(4‐tert‐butylphenolate)s [Ln(OTBP)₃] for the first time. The influences of reaction conditions on the copolymerization initiated by La(OTBP)₃ have been examined in detail. The monomer reactivity ratios of DTC and CL determined by the Fineman–Ross method are 4.0 for r_DTC and 0.27 for r_CL. The microstructure of the copolymer was determined by the analyses of the diads DTC–DTC, DTC–CL, CL–DTC and CL–CL of the ¹H NMR spectra. The high degree of randomness of the chain structure was further confirmed by the ¹³C NMR spectra and differential scanning calorimetry. The thermal properties of the copolymers as a function of composition are reported. The mechanism investigated by ¹H NMR data indicates that the rare‐earth tris(4‐tert‐butylphenolate)s initiate the ring‐opening copolymerization of DTC and CL with acyl‐oxygen bond cleavages of the monomers. Copyright © 2004 Society of Chemical Industry     

Biodegradations of statistical copolymers composed of D,L‐lactide and cyclic carbonates

Syntheses and biodegradation of statistical copolymers of D ,L ‐lactide (D ,L ‐LA) with trimethylene carbonate (TMC), rac‐1‐methyltrimethylene carbonate (1‐MTMC) and 2,2‐dimethyltrimethylene carbonate (2,2‐DTMC) were investigated at various monomer ratios using SmMe(C₅Me₅)₂THF as an initiator at 80 °C for 24 h in toluene. Biodegradations of poly(D ,L ‐LA‐co‐racemo‐1‐MTMC) (95/5) and poly(D ,L ‐LA‐co‐2,2‐DTMC) (98/2) with a compost at 60 °C proceed rapidly. Enzymatic degradations of these polymers were also performed using cholesterol esterase, lipoprotein lipase and proteinase K. Only poly(D ,L ‐LA‐co‐TMC) was biodegraded with cholesterol esterase, while poly(TMC), poly(1‐MTMC), poly(2,2‐DTMC) and poly(D ,L ‐LA) were barely degraded with these enzymes. Biodegradations of poly(D ,L ‐LA‐co‐TMC) (87/13) and poly(D ,L ‐LA‐co‐racemo‐1‐MTMC) (95/5) are rapid using proteinase K. Physical properties of these copolymers were also described. © 2003 Society of Chemical Industry     

Microwave‐assisted one‐pot copolymerization of cyclic monomers and ethyl diazoacetate

The present contribution describes an innovation in the copolymerization of cyclic monomers, ε‐caprolactam (ε‐CL) and 2,2‐dimethyltrimethylene carbonate (DTC), with ethyl diazoacetate (EDA). The characterizations of the obtained copolymers, poly(EA‐ran‐EDA‐ran‐ε‐CL) and poly(EA‐ran‐EDA‐ran‐DTC) (where EA refers to the ethyl acetate group from EDA after nitrogen release), were performed using ¹H NMR and ¹³C NMR spectroscopies and size exclusion chromatography. Under optimized conditions, the copolymer of ε‐CL with EDA possessing a number‐average molar mass (M_n) of 1300 g mol^?1 and dispersity of 2.12 as well as that of DTC with EDA with M_n of 8000 g mol^?1 and dispersity of 1.47 were obtained. The incorporation of the azo group in the obtained copolymers was determined from the results of elemental analysis (3.30–10.22% nitrogen) and Fourier transform infrared spectroscopy. Furthermore, the thermal properties of the obtained copolymers were examined using differential scanning calorimetry. X‐ray diffraction results showed that the synthesized copolymers were amorphous. © 2014 Society of Chemical Industry     

Synthesis and characterization of novel biodegradable poly(carbonate‐co‐phosphate)s

A series of aliphatic poly(carbonate‐co‐phosphate)s was synthesized in bulk using aluminium isopropoxide as initiator by ring‐opening polymerization with various cyclic carbonates (trimethylene carbonate (TMC) and 5,5‐dimethyltrimethylene carbonate (DTC)) and cyclic phosphates (ethylene ethyl phosphate (EEP), ethylene isobutyl phosphate (EIBP), ethylene lauryl phosphate (ELP) and ethylene stearyl phosphate (ESP)). The influence of reaction conditions such as polymerization time, polymerization temperature and initiator concentration on the yield and molecular weight were investigated. The substituent effect of the cyclic monomers on the polymerization was also studied, and the results indicate that the substituents exert a marked influence on the molecular weight of the copolymers obtained. The comonomer reactivity ratios were determined (TMC 0.88 and EEP 1.17). The copolymers with backbone chains rich in phosphate content exhibit better hydrophilicity than that of TMC homopolymer, and the degradation rate of the copolymers increases with the increase of phosphate content therein. © 2001 Society of Chemical Industry     

Synthesis and properties of polycarbonate copolymers of trimethylene carbonate and 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate

The polycarbonate copolymers poly[trimethylene carbonate‐co‐2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate] [P(TMC‐co‐PTC)] were synthesized by the ring‐opening polymerization of trimethylene carbonate (TMC) and 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate (PTC) with tin(II) 2‐ethylhexanoate and aluminum isopropoxide as the catalysts. These copolymers were further reduced by a palladium/carbonate (Pd/C; 10%) catalyst to produce partly deprotected copolymers. These two types of copolymers were characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, UV spectroscopy, gel permeation chromatography, differential scanning calorimetry, and an automatic contact angle meter. The influences of the feed molar ratio of the monomers, the catalyst concentration, the reaction time, and the reaction temperature on the copolymerization process were also studied. The copolymerization of the TMC and PTC monomers was a nonideal copolymerization, and the copolymerization reactivity ratio of TMC was higher than that of PTC. In vitro degradation tests indicated that the partly deprotected copolymers possessed faster degradation rates and more hydrophilicity than the corresponding unreduced copolymers. Moreover, the degradation of these two type copolymers increased when the pH value of the buffer solutions decreased. In vitro drug‐release experiments showed that these two types of copolymers had steady drug‐release rates and good controlled release properties. Moreover, the partly deprotected copolymers had faster drug‐release rates than the corresponding unreduced copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Poly(2,2-dimethyltrimethylene carbonate)-block-poly(dimethylsiloxane)-block-poly(2,2-dimethyltrimethylene carbonate). Synthesis and thermal properties

Lithium salts of hydroxytelechelic poly(dimethylsiloxane) [poly-(DMS)] were used as initiators for the anionic ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC). Triblock copolymers were obtained in high yields. Complexation of the active site in DTC polymerization by the poly(DMS) chain leads to a decrease in polymerization rate. The thermal properties of the copolymers of different compositions were determined. Catalysed thermal degradation of the block copolymers leads to cyclic oligomers D_n and DTC upon ring-closing depolymerization.     

Synthesis and characterization of ABA‐type block copolymers of trimethylene carbonate and ϵ‐caprolactone

This paper describes the synthesis of a series of ABA‐type triblock copolymers of trimethylene carbonate and ?‐caprolactone with various molar ratios and analyses the thermal and mechanical properties of the resulting copolymers. The structures of the triblock copolymers were characterized by ¹H and ¹³C nuclear magnetic resonance spectroscopy, FT‐IR spectroscopy and gel permeation chromatography. Results obtained from the various characterization methods proves the successful synthesis of block copolymers of trimethylene carbonate and ?‐caprolactone. The thermal properties of the block copolymers were investigated by differential scanning calorimetry. The T_m and ΔH_m values of the copolymers decrease with increasing content of trimethylene carbonate units. Two T_gs were found in the copolymers. Furthermore, both of the T_g values increased with increasing content of trimethylene carbonate units. The mechanical properties of the resulting copolymers were studied by using a tensile tester. The results indicated that the mechanical properties of the block copolymers are related to the molar ratio of trimethylene carbonate and ?‐caprolactone in the copolymers, as well as the molecular weights of the resulting copolymers. The block copolymer with a molar composition of 50/50 possessed the highest tensile stress at maximum and modulus of elasticity. Block copolymers possessing different properties could be obtained by adjusting the copolymer compositions. Copyright © 2004 Society of Chemical Industry     

Polycarbonate microspheres containing tumor necrosis factor‐α genes and magnetic powder as potential cancer therapeutics

Amphiphilic polycarbonate copolymers including methoxy‐terminated poly(ethylene glycol)‐co‐poly (5,5‐dimethyl trimethylene carbonate) [Poly(PEG‐b‐TMC)] and poly(ethylene glycol)‐co‐poly(trimethylene carbonate) [Poly(PEG‐b‐DTC)] were synthesized. The water‐in‐oil‐in‐water (W/O/W) solvent evaporation technique was adopted to produce anticancer magnetic Poly(PEG‐b‐DTC) microspheres containing tumor necrosis factor‐α (TNF‐α) genes and Fe₃O₄ magnetic ultrafine powder. Drug release studies showed that the microspheres can sustain a steady release rate of TNF‐α genes in 0.1M phosphate buffer saline solution in vitro for up to 60 h. In vitro cytotoxicity assays demonstrated that the microspheres have high inhibition and antitumor action to human hepatocellular carcinoma (Bel‐7204) cells in vitro. In vivo inhibition on the growth of hepatic carcinomas and histopathologic observation indicated that the microspheres possess a markedly high antitumor activity to human hepatocellular carcinoma (Bel‐7204). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fully degradable antibacterial poly(ester‐phosphoester)s by ring‐opening polymerization, “click” chemistry,and quaternization

Fully degradable cationic poly(ester‐phosphoester)s with antibacterial properties were prepared by a combination of ring‐opening polymerization (ROP) and “click” reaction. First, poly(ester‐phosphoester)s‐bearing alkynyl groups were synthesized by the ring‐opening copolymerization of 2‐(2‐propynyloxy)?2‐oxo‐1,3,2‐dioxaphospholane (propynyl ethylene phosphate, PEP) and ε‐caprolactone (CL) using lanthanum tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s (La(DBMP)₃) as the catalyst. 2‐Azido‐N,N‐dimethylethanamine (DMEAN₃) was then attached to the copolymers by “click” reaction, resulting in poly(ester‐phosphoester)s with pendant tertiary amines. After the quaternization reactions between the copolymer and various alkyl bromides, cationic poly(ester‐phosphoester)s containing ammonium groups were obtained. Optical density (OD) measurement shows that the cationic copolymers have excellent antibacterial activity, which makes them potential candidates as biomaterials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42647.     

The influence of 4HB content on the properties of poly(3‐hydroxylbutyrate‐co‐4‐hydroxylbutyrate) based on melt molded sheets

A series of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)s[P(3HB‐co‐4HB)s] sheets with the 4HB contents from about 9 to 34 mol % were prepared via melt molding. Their crystallinity, crystalline structures, thermal and mechanical properties were characterized by differential scanning calorimetry, X‐ray diffraction, thermogravimetric analysis, dynamic mechanical analysis, and tensile test. It was found that the melt temperatures (T_m), glass transition temperatures (T_g), and storage modulus (E′) of all the [P(3HB‐co‐4HB)s] copolymers investigated decreased continuously with increasing the amount of the 4HB; the yield stress and breaking stress nearly decreased with the increase of the 4HB contents while the elongation at the yield and break points increased; and the thermal stability of the P(3HB‐co‐4HB)s improved with increasing 4HB contents. The results suggest that the mechanical properties and crystal lattice parameters of the melt molded sheets are somewhat different from those of the solution cast films. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Aliphatic–aromatic poly(butylene carbonate‐co‐terephthalate) random copolymers: Synthesis,cocrystallization, and composition‐dependent properties

A series of aliphatic–aromatic poly(carbonate‐co‐ester)s poly(butylene carbonate‐co‐terephthalate)s (PBCTs), with weight‐average molecular weight of 113,000 to 146,000 g/mol, were synthesized from dimethyl carbonate, dimethyl terephthalate, and 1,4‐butanediol via a two‐step polycondensation process using tetrabutyl titanate as the catalyst. The PBCTs, being statistically random copolymers, show a single T_g over the entire composition range. The thermal stability of PBCTs strongly depends on the molar composition. Melting temperatures vary from 113 to 213°C for copolymers with butylene terephthalate (BT) unit content higher than 40 mol %. The copolymers have a eutectic melting point when about 10 mol % BT units are included. Crystal lattice structure shifts from the poly(butylene carbonate) to the poly(butylene terephthalate) type crystal phase with increasing BT unit content. DSC and WAXD results indicate that the PBCT copolymers show isodimorphic cocrystallization. The tensile modulus and strength decrease first and then increase according to copolymer composition. The enzymatic degradation of the PBCT copolymers was also studied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41952.     

Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K₂S₂O₈ as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, ¹H and ¹³C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H₂O) and washed with LiOH_(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006     

Eco‐plastics: Morphological and mechanical properties of recycled poly(carbonate)‐crushed rubber (rPC‐CR) blends

Crushed tire rubber particles (CR) have been dispersed into a recycled poly(carbonate) matrix (rPC) to obtain an eco‐friendly plastic (EFP). A positive synergy was expected from the association of an elastomeric phase to a tough thermoplastic matrix, helping on the other hand to develop a plastic with low impact on the environment. Mechanical melt‐mixing alone cannot provide a suitable interface, and led to blends with poor mechanical properties. Consequently, we have investigated different strategies to improve the EFP properties: First, the rubber surface has been treated by flaming or washing with dichloromethane and second, two copolymers, poly(ethylene‐co‐ethyl acrylate‐tert‐hydroxyl methacrylate) (E‐EA‐MAH) and poly(ethylene‐co‐methyl acrylate‐ter‐glycidyl methacrylate) (E‐MA‐GMA), were used to compatibilize CR particles with rPC matrix by reactive melt‐mixing in an internal mixer. The resulting blends mechanical properties were studied through static tension experiments and interpreted to the light of electronic microscopy fractography analysis and nanoindentation experiments. Significant gain of mechanical properties can be obtained by decreasing CR size under 140 μm (especially for CR contents between 5 and 20% m/m). To reach similar properties with rubber particles of diameter over 140 μm (but under 350 μm), it is necessary to activate their surface by either dichloromethane washing or flaming. Additional use of a compatibilizer extends the plastic behaviour domain of the EFP. rPC‐20% w/w CR is the best alternative material of our study. POLYM. ENG. SCI., 47:1768–1776, 2007. © 2007 Society of Plastics Engineers     

Synthesis and biological activity of medium molecular weight polymers containing 3,6‐endo‐methylene‐1,2,3,6‐tetrahydrophthalimidobutanoyl‐5‐fluorouracil

A new monomer, 3,6‐endo‐methylene‐1,2,3,6‐tetrahydrophthalimidobutanoyl‐5‐fluorouracil (ETBFU), was synthesized by reaction of 3,6‐endo‐methylene‐1,2,3,6‐tetrahydrophthalimidobutanoyl chloride and 5‐fluorouracil. The homopolymer of ETBFU and its copolymers with acrylic acid (AA) or vinyl acetate (VAc) were prepared by photopolymerization using 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C. The synthesized ETBFU and its polymers were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The ETBFU content in poly(ETBFU‐co‐AA) and poly(ETBFU‐co‐VAc) was 43 and 14 mol%, respectively. The apparent number‐average molecular weight (M_n) of the polymers determined by GPC ranged from 8400 to 11 300. The in vitro cytotoxicity of the samples against mouse mammary carcinoma (FM3A), mouse leukaemia (P388), and human histiocytic lymphoma (U937) cancer cell lines decreased in the order 5‐FU ≥ ETBFU > poly(ETBFU) > poly(ETBFU‐co‐AA) > poly(ETBFU‐co‐VAc). The in vivo antitumour activity of the polymers against Balb/C mice bearing sarcoma 180 tumour cells was greater than that of 5‐fluorouracil at all doses tested. © 2000 Society of Chemical Industry     

Shape‐memory behaviors of biodegradable poly(L‐lactide‐co‐ϵ‐caprolactone) copolymers

A series of biodegradable poly(L ‐lactide‐co‐?‐caprolactone) (PCLA) copolymers with different chemical compositions are synthesized and characterized. The mechanical properties and shape‐memory behaviors of PCLA copolymers are studied. The mechanical properties are significantly affected by the copolymer compositions. With the ?‐caprolactone (?‐CL) content increasing, the tensile strength of copolymers decreases linearly and the elongation at break increases gradually. By means of adjusting the compositions, the copolymers exhibit excellent shape‐memory effects with shape‐recovery and shape‐retention rate exceeding 95%. The effects of composition, deformation strain, and the stretching conditions on the recovery stress are also investigated systematically. A maximum recovery stress around 6.2 MPa can be obtained at stretching at T_g ? 15°C to 200% deformation strain for the PCLA70 copolymer. The degradation results show that the copolymers with higher ?‐CL content have faster degradation rates and shape‐recovery rates, meanwhile, the recovery stress can maintain a relative high value after 30 days in vitro degradation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and applicability of functionalized polyethylene with an ethylene/1,7‐octadiene copolymer

The copolymerization of ethylene and 1,7‐octadiene was carried out to synthesize polyethylene with unreacted vinyl groups. The prepared copolymer [poly (ethylene‐co‐1,7‐octadiene) (PEOD)] was epoxidized with peracetic acid, m‐chloroperbenzoic acid, or formic acid/H₂O₂. Of these, peracetic acid gave the best results. Epoxidized PEOD was subjected to a reaction with 2‐mercaptobenzimidazole and poly(L ‐lactic acid). The bromination of PEOD was also performed in the presence of a Br₂/HBr solution at room temperature. The brominated poly(ethylene‐co‐1,7‐octadiene) (PEOD‐Br) was used as a macroinitiator for atom transfer radical polymerization. The polymerization of styrene, butyl methacrylate, and glycidyl methacrylate was performed in bulk or solution at 120°C with a PEOD‐Br/CuBr/2,2′‐dipyridyl initiator system. The thermal properties of the graft copolymers and the efficiency of the graft polymerization were investigated. These graft copolymers have potential applications as interfacial modifiers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and application of sulfonated poly(1‐octene‐co‐styrene)

In this article, 1‐octene and styrene was copolymerized by the supported catalyst (TiCl₄/ID/MgCl₂). Subsequently, by sulfonation reaction, sulfonated poly(1‐octene‐co‐styrene)s which were amphiphilic copolymers were prepared. The copolymerization behavior between 1‐octene and styrene is moderate ideal behavior. Copolymers prepared by this catalyst contain appreciable amounts of both 1‐octene and styrene. Increase in the feed ratio of styrene/1‐octene leads to increase in styrene content in copolymer and decrease in molecular weight. As the polymerization temperature increases, the styrene content in the copolymers increases, however, the molecular weight decreases. Hydrogen is an efficient regulator to lower the molecular weights of poly(1‐octene‐co‐styrene)s. The sulfonation degree of the sulfonated poly(1‐octene‐co‐styrene)s increased as the styrene content in copolymer increased or the molecular weight decreased. Thirty‐six hour is long enough for sulfonation reaction. The sulfonated poly(1‐octene‐co‐styrene)s can be used as effective and durable modifying agent to improve the wettability of polyethylene film and have potential application in emulsified fuels and for the stabilization of dispersions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical properties of block poly(propylene carbonate‐cyclohexyl carbonate) investigated by nanoindentation and DMA methodologies

To extend the practical application of poly(propylene carbonate) (PPC), the chemical methods were used to improve its mechanical properties. In this connection, random copolymer poly(propylene‐cyclohexyl carbonate) (PPCHC) and di‐block copolymers poly(propylene carbonate‐cyclohexyl carbonate) (PPC‐PCHC) were synthesized. Dynamic mechanical analysis (DMA), nanoindentation and nanoscratch test were applied to evaluate their mechanical properties. The storage's modulus, Young's modulus (E) and hardness (H) obtained from DMA and nanoindentation tests showed that the introduction of the third monomer cyclohexene oxide (CHO) can greatly improve the mechanical properties of PPC, and that the block copolymer PPC‐PCHC hand better mechanical properties than the random copolymer PPCHC. The annealing treated PPC‐PCHCs exhibited deteriorated mechanical properties as compared with untreated PPC‐PCHC. From the results of scratch tests, the plastic deformation of PPC‐PCHC was smaller than those of PPC and PPCHC. Meanwhile, the plastic deformations of the heat‐treated PPC‐PCHCs were smaller than the untreated PPC‐PCHC because of the possible rearrangement of the molecular chains of PPC‐PCHC. The scratch hardness (H_s) of the block copolymer PPC‐PCHC is larger than random polymer PPCHC and PPC, but lower than the values of heat‐treated samples indicating that the surfaces' hardness of block polymers increase after heat treatment. These different measurement methodologies provide a more precise assessment and understanding for the synthesized block polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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     

Carbon dioxide sorption and diffusion in poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐CO‐3‐hydroxyvalerate)

CO₂ sorption and diffusion in poly(3‐hydroxybutyrate) and three poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) copolymers were investigated gravimetrically at temperatures from 25° to 50°C and pressures up to 1 atm. The sorption behavior proved to be linear for all the copolymers studied. An additional set of measurements performed in a pressure decay apparatus at 35°C showed that the linearity could be extrapolated to pressures up to 25 atm. The sorption results obtained from both techniques were in good agreement. The poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) sorption kinetics were increasingly non‐Fickian at the higher temperatures, thus preventing the calculation of diffusion coefficients above 35°C. Interestingly, this was not the case for poly(3‐hydroxybutyrate), and diffusion coefficients and permeabilities could be calculated at all of the investigated temperatures. The 35°C permeabilities were fairly low, which is attributed to the high degree of crystallinity of this polyester family. Finally, the poly(3‐hydroxybutyrate) barrier properties against CO₂ are successfully compared with those of some selected common thermoplastics. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2391–2399, 1999