Thermal stability and decomposition mechanism of poly(p‐acryloyloxybenzoic acid and poly (p‐methacryloyloxybenzoic acid) and their graft copolymers with polypropylene,Part II

Thermal stability and decomposition mechanism of poly(p‐acryloyloxybenzoic) acid (PABA), p‐methacryloyloxybenzoic acid (PMBA), and their graft coproducts of PP were studied by differential scanning calorimetry, direct pyrolysis mass spectrometry, and TG/IR system, combined thermogravimetric analyzer, and FTIR spectrometer. The homopolymers and corresponding grafts were found to be stable in nitrogen atmosphere but started to decompose under atmospheric conditions when heated above 230°C. PABA and PAPA‐g‐PP showed a better thermal stability compared to the other polymer. The degradation proceeded predominantly by decomposition of side groups giving phenol, benzoic acid, hydroxybenzoic acid, carboxylic and carbonyl groups, and by decomposition of phenol into cyclodiene mainly. It was also seen that the degradation path did not greatly changed whether the PABA or PMBA were homopolymers or grafted onto PP but the induction temperature of grafted polymers was seen at some 10–20°C higher. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Graft copolymerization of acrylic acid on methylcellulose by ceric ion/p‐xylene redox pair

The graft copolymerization of acrylic acid onto methylcellulose by ceric ion/p‐xylene redox pair was investigated in aqueous media under homogeneous conditions. The graft yield dependency on p‐xylene concentration in the range 1.8–45.0 × 10^?5M showed a minimum and an enhanced yield when the methylcellulose interacted with ceric ion and p‐xylene for an initial period of 10 min (preoxidation time) prior to addition of monomer to the reaction medium. This was attributed to the presence of two kinetically controlled reactions initiated by p‐xylyl radical and diradical species. At prolonged preoxidation times of 30 and 60 min, the graft yield dependency on p‐xylene concentration was normal and suggested the presence of only one initiating species. The effect of ceric ion on the graft reaction in the concentration range of 8.33–83.3 × 10^?3M was optimal at 131% graft yield for ceric ion concentration of 16.7 × 10^?3M and was reduced significantly by as much as 75% at the highest concentration of the latter. The temperature dependency of graft yield was negative in the region 30–50°C. At 50°C the initial rate of graft was only 37% of the value at 30°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 500–504, 2002; DOI 10.1002/app.10200     

Synthesis and characterization of novel organotin monomers and copolymers and their antibacterial activity

Two novel organotin monomers, (N‐tri‐n‐butyltin) maleimide and m‐acryloylamino‐(tri‐n‐butyltin benzoate), were synthesized. Copolymerization of these two monomers with styrene was carried out in the bulk at 65°C using asobisisobutyronitrile as the free radical initiator. The monomers and copolymers were characterized by elemental analysis; the molecular weights of the copolymers were determined by GPC, solubility, IR, and ¹H‐NMR spectral studies. The antibacterial activities of the synthesized organotin monomers and copolymers toward various types of bacteria were also reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 740–745, 2000     

Bioengineering functional copolymers: V. Synthesis,LCST, and thermal behavior of poly(N‐isopropyl acrylamide‐co‐p‐vinylphenylboronic acid)

New boron‐containing stimuli‐responsive (pH‐ and temperature‐sensitive) copolymers were synthesized and characterized. Structure and composition of copolymers were determined by FTIR and ¹H‐NMR spectroscopy, and elemental analysis and titration (N and B contents for NIPA and VPBA unit, respectively). By DSC and XRD measurements, it is established that the synthesized copolymers have a semicrystalline structure due to formation of intra‐ and/or intermolecular H‐bonded supramolecular architecture. The copolymer composition–structure–property relationship indicates semicrystalline structure of copolymers with different compositions, degrees of crystallinity, and thermal and stimuli‐responsive behaviors depends on the content of boron‐containing monomer linkage. Results of DSC, DTA, and TGA analyses indicated that copolymers have T_g and T_m and high thermal stability. These water‐soluble and temperature‐ and pH‐sensitive amphiphilic copolymers can be used as polymeric carries for delivery of biological entities for diverse biomedical use, including boron neutron capture therapy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 573–582, 2005     

Graft copolymerization of p‐acryloyloxybenzoic acid and p‐methacryloyloxybenzoic acid onto isotactic polypropylene and their thermal properties: Part I

The polymerization and grafting of the monomers p‐acryloyloxybenzoic acid and p‐methacryloyloxybenzoic acid were studied. Poly(acryloyloxybenzoic acid) was obtained by γ‐radiation‐induced solution polymerization and bulk melt polymerization initiated by dicumyl peroxide. Poly(methacryloyloxybenzoic acid) could be obtained only by bulk melt polymerization. The graft copolymerization of the monomers onto isotactic polypropylene was carried out in bulk. The maximum grafting was reached in shorter times at higher temperatures, and it also increased with the concentration of the monomers in the reaction medium. The thermal and crystallization behavior of the graft copolymers was studied with differential scanning calorimetry and wide‐angle X‐ray diffraction. The graft copolymerization of p‐acryloyloxybenzoic acid did not have any influence on the formation of both α forms (monoclinic) of polypropylene, whereas p‐methacryloyloxybenzoic acid led to the α₂ form. The β‐crystalline modification (hexagonal) formed in poly(acryloyloxybenzoic acid)‐g‐polypropylene products at 185°C and at higher grafting temperatures and also in the second run of differential scanning calorimetry studies after fast cooling. The β form was not observed in graft copolymers of poly(methacryloyloxybenzoic acid). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal decomposition kinetics of thermotropic copolyesters made from trans‐p‐hydroxycinnamic acid and p‐hydroxybenzoic acid

A series of thermotropic copolyesters were synthesized by direct thermal melt polycondensation of p‐acetoxybenzoic acid (PHB) with trans‐p‐acetoxycinnamic acid (PHC). The dynamic thermogravimetric kinetics of the copolyesters in nitrogen were analyzed by four single heating‐rate techniques and three multiple heating‐rate techniques. The effects of the heating rate, copolyester composition, degradation stage, and the calculating techniques on the thermostability and degradation kinetic parameters of the copolyesters are systematically discussed. The four single heating‐rate techniques used in this work include Friedman, Freeman–Carroll, Chang, and the second Kissinger techniques, whereas the three multiple heating‐rate techniques are the first Kissinger, Kim–Park, and Flynn–Wall techniques. The decomposition temperature of the copolyesters increases monotonically with increasing PHB content from 40 to 60 mol %, whereas their activation energy exhibits a maximal value at the PHB content of 50 mol %. The decomposition temperature, activation energy, the order, and the frequency factor of the degradation reaction for the thermotropic copolyester with PHB/PHC feed ratio of 50/50 mol % were determined to be 374°C, 408 kJ/mol, 7.2, and 1.25 × 10²⁹ min^?1, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 445–454, 2004     

Water‐soluble copolymers from functionalized monomers (sodium o‐ and p‐methacryloylaminophenylarsonate): Synthesis and characterization

Copolymers of sodium o‐methacryloylaminophenylarsonate (o‐MAPHA‐Na) 1 and p‐methacrylolylaminophenylarsonate (p‐MAPHA‐Na) 2 with sodium acrylate (AA‐Na) 3 , sodium methacrylate (AM‐Na) 4 and acrylamide (AAD) 5 were prepared by free radical polymerization in aqueous media at 70°C using potassium persulfate (K₂S₂O₈) as the initiator. The total monomer concentration was carried out at 0.5M and the feed ratio ( M₁ : M₂ ) was varied from 10 : 90 to 90 : 10 mol%. The kinetic study was carried out by dilatometric method. The copolymer compositions were calculated by arsenic content in the copolymers. The As content (ppm) was determined by atomic absorption spectrometry (AAS). The reactivity ratios (r₁, r₂) were estimated by the Kelen‐Tüdös linearization method as well as error‐in‐variables method using the computer program RREVM®. In all cases, r₁ < 1 and r₂ > 1, indicating a tendency to form random copolymers. The values suggest that the copolymers contain a larger proportion of comonomer (i.e., AA‐Na, AM‐Na, or AAD). Weight‐average molar masses (M _w) of copolymers were determined by multi‐angle light scattering. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group—part 7. Copolymerization of tetrafluoroethylene with ω‐hydroxy trifluorovinyl monomers

The radical copolymerization of tetrafluoroethylene (TFE) and trifluorovinyl ω‐hydroxy comonomers [F₂CCF(CH₂)_mOH with m = 1 (FA1) and m = 3 (FA3)] for the synthesis of fluorinated polymers bearing hydroxy side groups is presented. FA1 was prepared by dehydrofluorination of 2,2,3,3‐tetrafluoropropanol, whereas FA3 was obtained in a three‐step scheme starting from the radical addition of 1,2‐dichloroiodotrifluoroethane to allyl alcohol. The copolymerization conditions (in bulk or in solution in di n‐butyl ether) and the polymer compositions considerably influenced the molecular weights, the molecular weight distributions, and the thermal properties of these copolymers. The kinetics of copolymerization of both couples enabled to determine the reaction order to the initiator (being 0.9) and the close values of apparent activation energies for [TFE/FA1 (E_a = 52.4 kJ · mol⁻¹) and for TFE/FA3 (E_a = 46.8 kJ · mol⁻¹)] couples. From the Tidwell and Mortimer method, the relative reactivity ratios were calculated by elemental analysis or by ¹⁹F‐NMR spectroscopy, showing a higher reactivity of the TFE to incorporate the copolymer (r_TFE = 2.47 and r_FA1 = 0.41; r_TFE = 1.57 and r_FA3 = 0.45). The high values of the reaction order to the initiator and low molecular weights of copolymers were associated to the allylic chain transfer of the hydroxy comonomers and a mechanism of copolymerization was proposed. The comonomer diad and triad distribution was determined by the statistic theory and allowed one to calculate the average length of the comonomer sequences. Finally, the thermal decomposition of these cooligomers showed that those containing FA3 units are more thermostable than those synthesized from FA1, and that the higher the fluorinated alcohol content, the faster the thermal decomposition. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 189–202, 1999     

Peroxydiphosphate–metal ion–cellulose thiocarbonate redox system‐induced graft copolymerization of vinyl monomers onto cotton fabric

The grafting of methacrylic acid (MAA) and other vinyl monomers onto cotton cellulose in fabric form was investigated in an aqueous medium with a potassium peroxydiphosphate–metal ion–cellulose thiocarbonate redox initiation system. The graft copolymerization reaction was influenced by peroxydiphosphate (PP) concentration, the pH of the reaction medium, monomer concentration, the duration and temperature of polymerization, the nature of vinyl monomers, and the nature and concentration of metallic ions (activators). On the basis of a detailed investigation of these factors, the optimal conditions for the grafting of MAA onto cotton fabric with the said redox system were as follows: [Fe²⁺] = 0.1 mmol/L, [PP] = 2 mmol/L, [MAA] = 4%, pH‐2, grafting time = 2 h, grafting temperature = 70°C, and material/liquor ratio = 1 : 50. Under these optimal conditions, the graft yields of different monomers were in the following sequence: MAA ? acrylonitrile > acrylic acid > methyl acrylate > methyl methacrylate. The unmodified cellulosic fabric (the control) had no ability to be grafted with MAA with the PP–Fe²⁺ redox system. The percentage of grafting onto the thiocarbonated cellulosic fabric was more greatly enhanced in the presence of iron salts than in their absence. This held true when the lowest concentrations of these salts were used separately. A suitable mechanism for the grafting processes is suggested, in accordance with the experimental results. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1879–1889, 2003     

Copolymerization of propylene with p‐allyltoluene using metallocene catalysts

Copolymerization of propylene with p‐allyltoluene (p‐AT) was performed using two metallocene catalysts, rac‐ethylenebis(indenyl)zirconium dichloride and rac‐dimethylsilylenebis[1‐(2‐methyl‐4‐phenylindenyl)]zirconium dichloride. The effects of the polymerization conditions, such as the amount of p‐AT in the feed and polymerization temperature, on the properties of the copolymers and the activity of the catalysts were investigated. With increasing p‐AT feed, the incorporation of p‐AT increased, but the activity of the metallocene catalyst, the melting temperature (T_m) and the number‐average molecular weight of the copolymers decreased. Higher polymerization temperature tended to enhance the activity of the metallocene catalyst and the incorporation of p‐AT. The copolymers produced using the two metallocene catalysts were characterized with ¹H NMR, ¹³C NMR and differential scanning calorimetry; the results showed that the copolymers had a random structure. Copyright © 2006 Society of Chemical Industry Society of Chemical Industry     

Synthesis and properties of poly(acrylonitrile‐co‐p‐trimethylsilylstyrene) and poly(acrylonitrile‐co‐p‐trimethylsilylstyrene‐co‐styrene)

Copolymerization of acrylonitrile (AN) with p‐trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M₁) and TMSS (M₂) were determined to be r₁ = 0.068 and r₂ = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl₄ on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl₄ in solution led to a decrease in MW. Poly(AN‐co‐TMSS‐co‐St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) with commercial poly(AN‐co‐St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X‐ray photoelectron spectroscopy. The data obtained indicate that the silicon‐containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000     

Synthesis and characterization of new polyamides containing p‐phenylenediacryloyl moieties in the main chain

Six new polyamides 8a–f containing p‐phenylenediacryloyl moieties in the main chain were prepared by the direct polycondensation reaction of bis(p‐amidobenzoic acid)‐p‐phenylene diacrylic acid 6 with 1,4‐diphenylene diamine 7a , 1,3‐diamino toluene 7b , 1,5‐diamino naphthalene 7c , 4,4′‐diamino diphenyl ether 7d , 4,4′‐diamino diphenyl sulfone 7e , and 3,3′‐diamino diphenylsulfone 7f by using thionyl chloride, N‐methyl‐2‐pyrolidone, and pyridine as condensing agents. These new polymers 8a–f were obtained in high yield and inherent viscosity between 0.35–0.65 dL/g. The resulting polyamides were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test, FTIR and UV–vis spectroscopy. Diacid acid 6 as a new monomer containing p‐phenylenediacryloyl moiety was synthesized by using a three‐step reaction. First, p‐phenylenediacrylic acid 3 was prepared by reaction of terephthal aldehyde 1 with malonic acid 2 in the presence of pyridine, then diacid 3 was converted to p‐phenylenediacryloyl chloride 4 by reaction with thionyl chloride. Finally, bis(p‐amidobenzoic acid)‐p‐phenylene diacrylic acid 6 was prepared by the condensation reaction of phenylenediacryloyl chloride 4 with p‐aminobenzoic acid 5 . © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Copolymers of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate: Synthesis and herbicide release

Free‐radical copolymerization of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate using 1.0 mol/L 1,4‐dioxane solution and 1.5 × 10^?2 mol/L of 2,2′ azobisisobutyronitrile as initiator has been carried out at 50°C. In addition to low conversion solution experiments performed to estimate the monomer reactivity ratios, three different copolymerizations over the whole range of conversions have been made. Theoretical values of cumulative copolymer composition, determined by the Mayo‐Lewis terminal model, have been correlated with those experimentally obtained. Finally, the herbicide release in three different aqueous pH buffer solutions has been evaluated in heterogeneous phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4238–4244, 2006     

Synthesis and characterization of poly(urethane‐ether)s from calcium salt of p‐hydroxybenzoic acid

The synthesis and characterization of calcium‐containing poly(urethane‐ether)s, having ionic links in the main chain, is reported. Calcium salt of p‐hydroxybenzoic acid (HBA‐Ca) was prepared from p‐hydroxybenzoic acid (HBA) and used as the chain extender in the preparation of calcium‐containing poly(urethane‐ether)s. Poly(urethane‐ether)s, having two different compositions, were prepared by varying the mole ratios of poly(tetramethylene glycol), hexamethylene diisocyanate, and HBA‐Ca. The synthesized poly(urethane‐ether)s were characterized by infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analysis. The presence of calcium in the polymer chain was confirmed by energy‐dispersive X‐ray analysis. The inherent viscosity of metal‐containing polymers decreased with the increase in the metal content of the polymer. The introduction of metal into the polymer lowers the thermal stability of the polymers as indicated by the decreased initial decomposition temperature. The glass transition temperature (T_g) and the storage modulus of the metal‐containing polymers increase with the increase in metal content presumably due to the formation of physical crosslink's in the polymer. From the mechanical studies of the polymer, it was observed that the metal‐containing polymers exhibit high tensile strength and modulus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Synthesis of superabsorbent starch‐graft‐poly(potassium acrylate‐co‐acrylamide) and its properties

The superabsorbent's ability to resist deformation and to resist deswelling under externally applied pressures is important in practical application. For instance, it is used in infant diapers, in soil for agriculture, and in forestry. In this article, we report on the synthesis of a superabsorbent/starch‐graft‐poly(potassium acrylate‐co‐acrylamide) by inverse suspension polymerization. The effects of reaction conditions, such as monomeric concentration, ratio of water to oil, reaction temperature, and obtaining spherical resin, were investigated. Experiments showed that the superabsorbent has a good compressive strength and keeps the shape of particles after absorbing water. After mixing with soil it does not become sticky, and the loose structure can better retain air. It is fit to retain water in soil. In addition, thermogravimetric analysis revealed the superior thermal stability of the grafted product and its large particle size also reduces risk of air pollution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1536–1542, 2003     

Benzoyl peroxide–p‐acetylbenzylidenetriphenyl arsoniumylide initiated copolymerization of citronellol and styrene

Alternating copolymers, containing styrene and citronellol sequences, have been synthesized by radical polymerization using benzoylperoxide (BPO)–p‐acetylbenzylidenetriphenyl arsoniumylide (pABTAY) as initiator, in xylene at 80 ± 1 °C for 3 h under inert atmosphere. The kinetic expression is R_p ∝ [BPO]^0.88 [citronellol]^0.68 [styrene]^0.56 with BPO and R_p ∝ [pABTAY]^0.27 [citronellol]^0.76 [styrene]^0.63 with pABTAY, ie the system follows non‐ideal kinetics in both cases, because of primary radical termination and degradative chain transfer reactions. The activation energy with BPO and pABTAY is 94 kJ mol^?1 and 134 kJ mol^?1, respectively. Different spectral techniques, such as IR, FTIR, ¹H NMR and ¹³C NMR, have been used to characterize the copolymer, demonstrating the presence of alcoholic and phenyl groups of citronellol and styrene. The alternating nature of the copolymer is shown by the product of reactivity ratios r₁ (Sty) = 0.81 and r₂ (Citro) = 0.015 using BPO and r₁ (Sty) = 0.37 and r₂ (Citro) = 0.01 using (pABTAY), which are calculated by the Finemann–Ross method. A mechanism of copolymerization is proposed. © 2001 Society of Chemical Industry     

Synthesis,characterizations and thermal behavior of methyl methacrylate and N‐(p‐carboxyphenyl) methacrylamide/acrylamide copolymers

The synthesis, characterization, and thermal properties of copolymers of methyl methacrylate (MMA) and N‐(p‐carboxyphenyl) methacrylamide/acrylamide (CPMA/CPA) are described. The copolymerization was carried out in solution by taking different mole fractions (0.1–0.5) of CPMA/CPA in the initial feed using azobisisobutyronitrile as an initiator and dimethylformamide as a solvent at 60°C. The copolymer composition was determined from ¹H‐NMR spectra by taking the ratio of the proton resonance signal due to the  OCH₃ of MMA (δ = 3.59 ppm) and the aromatic protons (δ = 7.6–7.8 ppm) of CPMA/CPA. The monomer reactivity ratios of MMA:CPMA and MMA:CPA were determined using the Fineman Ross and Kelen Tudos methods and were found to be 1.32 ± 0.01 [MMA], 1.11 ± 0.02 [CPMA], 2.60 ± 0.01 [MMA], and 0.20 ± 0.01 [CPA]. Incorporation of these comonomers in the MMA backbone resulted in an improvement in the glass‐transition temperature and thermal stability. The percent char also increased with the increase of CPMA/CPA content in the copolymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 259–267, 2000     

Synthesis of imide‐based methacrylic monomers and their copolymerization with methyl methacrylate: monomer reactivity ratios and heat resistance properties

The newly designed methacrylic monomer series 4‐phthalimidocyclohexyl methacrylate (PCMA ), 4‐hexahydrophthalimidocyclohexyl methacrylate (HPCMA) and 4‐hexahydro‐3,6‐methanophthalimidocyclohexyl methacrylate (HMPCMA) were synthesized. Their homopolymers and methyl methacrylate (MMA) based copolymer series were polymerized by free‐radical polymerization. The copolymer compositions were characterized using ¹H NMR spectra. The monomer reactivity ratios were calculated employing the Fineman?Ross (F‐T) and Kelen?Tüdös (K‐T) methods at low conversion. The values of r₁ and r₂ obtained by the F‐T and K‐T methods appear to be in close agreement (their average values are r₁ = 1.3061 and r₂ = 0.7336 for poly(PCMA‐co‐MMA), r₁ = 1.5169 and r₂ = 0.6840 for poly(HPCMA‐co‐MMA), r₁ = 1.7748 and r₂ = 0.5664 for poly(HMPCMA‐co‐MMA)) . The thermal stabilities and thermomechanical characteristics of the homopolymer and copolymer series were investigated by differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical thermal analysis. © 2018 Society of Chemical Industry     

Regulating the physical and biological performances of poly(p‐dioxanone) by copolymerization with L‐phenylalanine

The high crystallinity, low solubility in normal solvents, and low hydrophilicity of poly(p‐dioxanone) (PPDO) are unsuitable for the expansion of its biomedical applications. In order to circumvent these problems and induce biological properties, a series of poly(ester amide)s based on p‐(dioxanone) and l ‐phenylalanine were synthesized by copolymerization of p‐dioxanone with l ‐phenylalanine N‐carboxyanhydride monomers. The structures of the copolymers were confirmed by ¹H NMR. The crystallinity of the copolymers was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Increasing contents of phenylalanine resulted in decreased crystallinity owing to the rigid phenyl groups of phenylalanine, which disrupted the regularities of the chains, thus confining their movement. The synthesized copolymers were more soluble in chloroform than PPDO. Moreover, the copolymers were more hydrophilic and hydrolyzed more slowly than PPDO, as indicated by water angle contact measurements and in vitro hydrolysis studies. Especially, the copolymers showed inhibition on cell proliferation of L929 mouse fibroblasts by MTT assay, suggesting that the polymers might be useful in the areas where cell proliferation need to be inhabited such as adhesion prevention. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2311–2319, 2013     

Synthesis of p‐aminophenol from the hydrogenation of nitrobenzene over metal–solid acid bifunctional catalyst

BACKGROUND: A single‐step conversion of nitrobenzene (NB) to p‐aminophenol (PAP) through catalytic hydrogenation is a widely used synthesis route for PAP. The main shortcoming of this route is the use of sulfuric acid for rearrangement of the phenylhydroxylamine (PHA) intermediate. In this paper, S₂O₈^2?/ZrO₂ (PSZ) solid acid and Pt‐S₂O₈^2?/ZrO₂ (Pt‐PSZ) bifunctional catalysts were prepared for the synthesis of PAP in non‐acid medium. RESULTS: Calcination temperature has a substantial effect on the acidity, structure and activity for PHA rearrangement of PSZ. The highest PAP yield was 33.8% over PSZ calcined at 823 K when the reaction was carried out in water at 423 K. A high PAP yield of 23.9% was achieved by a single‐step reaction of nitrobenzene over Pt‐PSZ bifunctional catalysts. CONCLUSION: PSZ solid acid exhibits high activity for PHA rearrangement. Perfect tetragonal ZrO₂ and much stronger acid sites play important roles in catalytic activity. Inhibiting the hydrogenation activity by reducing the amount of Pt loading on Pt‐PSZ can improve the competition of PHA rearrangement on acid sites with hydrogenation of PHA on metal active sites, resulting in better selectivity to PAP. Copyright © 2008 Society of Chemical Industry