Graft Copolymerization of Methyl Methacrylate onto Poly(Ethylene Terephthalate) Fibers Using Benzoyl Peroxide

Abstract

The graft copolymerization of methyl methacrylate onto poly(ethylene terephthalate) fibers has been studied using benzoyl peroxide as initiator. The grafting reactions were carried out within the 70 to 90°C temperature range, and the variations of graft yield with monomer and initiator concentrations were also investigated. The overall activation energy for grafting was calculated as 34.1 kcal/mol. The results of dyeability with the disperse dye suggested that diffusion into the fiber structure was moderately difficult when the graft yield reached 14?15%. The maximum graft yield was obtained at a benzoyl peroxide concentration of 4.00 × 10^?3 M. The decomposition temperature values obtained from thermogravimetric analysis show that the thermal stability of poly(ethylene terephthalate) fibers decreased as a result of grafting. Further, such change in the properties of methyl methacrylate grafted fibers as density, diameter, and moisture regain were also determined.     

Graft copolymerization of itaconic acid-methacrylamide comonomers onto poly(ethylene terephthalate) fibers

The graft copolymerization of itaconic acid-methacrylamide (IA-MAAm) comonomers was carried out using benzoyl peroxide as initiator onto poly(ethylene terephthalate) (PET) fibers in an aqueous medium. The grafted fibers were characterized by FTIR, TGA, DSC and SEM analysis. Effect of various parameters on graft yield such as feed composition, feed and initiator concentration, reaction time and temperature were investigated. The graft yield in the presence of MAAm increased because of the synergistic effect of MAAm comonomer. While, the graft yield alone with the IA onto PET fiber was 2.2%, the use of MAAm as a comonomer increased the amount of IA introduced to the PET fiber up to 13.7%. The reactivity ratios for both monomers were determined by using a Fineman-Ross plot. The grafting rate and saturation graft yield was increased upon increasing the temperature between 65 °C and 85 °C. When the temperature increased further than 85 °C, the saturation graft yield decreased. The graft yield has shown an increase up to an initiator concentration of 1.0 × 10⁻² M and slightly decreased. The grafting increased the dyeability with acidic and basic dyes, and moisture absorption capacity but decreased the thermal stability of the fibers.     

Graft Copolymerization of Methyl Methacrylate onto Nylon 6 Using Thallium(III) Ions as Initiator

Abstract

Graft copolymerization of methyl methacrylate onto nylon 6 was investigated in aqueous perchloric acid medium using thallium(III) ions as initiator. The rate of grafting was evaluated by varying the concentrations of monomer, initiator, acid, and temperature. The rate of grafting was found to increase with an increase of both monomer and initiator concentrations. The graft yield was found to increase with an increase in the acid concentration up to 0.49 mL^?1, and beyond this concentration of perchloric acid the graft yield was found to decrease. It also increased with an increase of temperature. From the Arrhenius plot the overall activation energy was found to be 3.9 kcal/mol. The effects of inhibitors, various solvents, inorganic salts, and swelling agents on graft yield were studied. A suitable kinetic scheme has been proposed and a rate equation has been derived.     

Grafting onto Wool. IX. Graft Copolymerization of Vinyl Monomers by Use of Vanadium Oxyacetylacetonate as Initiator

Methyl methacrylate (MMA), acrylic acid (AAc), and vinyl acetate (VAc) were graft copolymerized onto Himachali wool in an aqueous medium by using vanadium oxyacetyl acetonate as initiator. Graft copolymerization was studied at 45, 55, 65, and 75°C for various reaction periods. The percentage of grafting was determined as functions of concentration of monomers, concentration of initiator, time, and temperature. The maximum percentage of grafting with each monomer occurred at 55°. Several grafting experiments were carried out in the presence of various additives which include HNO3, DMSO, and pyridine. Nitric acid was found to promote grafting of MMA. All these additives had adverse effects on grafting of VAc and AAc. MMA, VAc, and AAc were found to differ in reactivity toward grafting and followed the order MMA > AAc > VAc.     

Grafting of Acrylamide On 1, 1, 2, 2-Tetra-Chloroethane Preswelled Polyethylene Terephthalate) Films Using Azobisisobutyronitrile Initiator

Abstract

Graft polymerization of acrylamide (AAm) on 1, 1, 2, 2 tetrachloro-ethane (TCE) preswelled poly(ethylene terephthalate) (PET) films were performed with chemical initiation method using asobisiso-butyronitrile (AIBN) initiator. Temperature was found to have a greater effect on the swelling then the swelling time. Variation of the graft yield with polymerization temperature, time, AIBN concentration, AAm concentration, AIBN and AAm inclusion times were investigated. The optimum temperature for grafting was found to be 70°CC. The graft yield was observed to increase with polymerization time, AAm concentration, initiator and monomer diffusion time up to a saturation graft yield and then leveled off. An increase in AIBN concentration first enhanced the percent grafting then showed a decrease. The addition of some salts (Ni²⁺, Cr³⁺, Co²⁺, Cu²⁺) on the rate of grafting was also investigated. From the temperature dependence of the initial rate of grafting, the overall activation energy was found to be 4. 1 kcal/mol and relevant rate equation have been derived. The effect of grafting on film propities, such as water absorption capacity, intrinsic viscosity were determined. Grafted films were characterized by FTIR spectros-copy and scanning electron microscopy (SEM).     

Graft Copolymerization of (Dimethylamino)Ethyl Methacrylate onto Chitosan Initiated by Ceric Ammonium Nitrate

Abstract

(Dimethylamino)ethyl methacrylate (DMAEMA) was grafted onto chitosan using ceric ammonium nitrate as initiator in acetic acid solution. The effects of reaction variables on the grafting percentage and efficiency percentage were investigated, including the amounts of monomer and initiator, reaction time and reaction temperature. The grafted copolymers were confirmed by FTIR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of TGA and DSC indicated the improvement of thermal stability for chitosan‐g‐poly(PDMAEMA). Solubility test revealed the improved hydrophilicity of grafted chitosan in aqueous acetic acid solution, and its swelled behavior in mixtures of glacial acetic acid and anhydrous ethanol (the ratios of 1:1 and 1:2, v/v). The grafted copolymer possessed amphiphilic structure and exhibited properties of polymeric surfactant.     

乙烯吡咯烷酮对PET薄膜的表面接枝改性

利用低温等离子体和UV诱导技术,制备具有较高生物相容性和亲水性的聚对苯二甲酸乙二醇酯(PET)-聚乙烯吡咯烷酮(PNVP)复合膜。利用衰减全反射傅里叶红外光谱(ATR-FTIR)、X射线光电子能谱(XPS)、原子力显微镜(AFM)对PET-PNVP复合膜表面的结构形态进行了系统表征,对影响接枝度的因素如引发剂浓度、UV辐射时间、单体浓度也做了系统分析。润湿性分析结果表明,接枝PNVP的PET膜表面亲水性得到了有效改善。体外血液相容性实验表明PET-PNVP复合膜具有较好的血液相容性。噻唑蓝比色法(MTT法)细胞毒性实验表明,PETPNVP复合膜没有细胞毒性。     

UV-induced Self-initiated Graft Polymerization of Acrylamide onto Poly(ether ether ketone)

Photo-grafting of hydrophilic monomer was used to enhance the hydrophilicity of poly(ether ether ketone) (PEEK) with the aim of extending its applications to biological fields. PEEK sheets were surface modified by grafting of acrylamide(AAm) with ultraviolet(UV) irradiation in the presence or absence of benzophenone(BP). The effects of BP, irradiation time and monomer concentration on the surface wettability of PEEK were investigated. Characterization of modified PEEK using scanning electron microscopy(SEM), energy-disperse spectrometer(EDS) and water contact angle measurements shows that AAm was successfully grafted on PEEK surface both in presence and absence of BP. With the increase in irradiation time and monomer concentration, contact angles decrease to as low as 30°, demonstrating a significant improvement of surface hydrophilicity. In agreement with the decrease in contact angle, under identical conditions, the nitrogen concentration increases, suggesting the increase in grafting degree of the grafting polymerization. This investigation demonstrates a self-initiation of PEEK due to its BP-like structure in the backbone of the polymer. Though the graft polymerization proceeds more readily in the presence of BP, the self-initiated graft polymerization is clearly observed.     

聚对苯二甲酸丙二醇酯(PTT)的研究

新型聚酯材料聚对苯二甲酸丙二醇酯(PTT)是一种极有应用潜力的聚合物，但在非纤维领域的研究与应用才刚开始。本文简要概述了其发展状况；详述其结构、性能特点；重点介绍PTT目前在非纤维领域的应用与研究进展。     

The interaction of vinyl monomers and poly (ethylene terephthalate) in the presence of various initiators produces a physical mixture,not a graft copolymer

The interaction between poly(ethylene terephthalate) and four vinyl monomers, methacrylic acid, methyl methacrylate, styrene, and vinyl acetate, has been studied using hydrogen peroxide, benzoyl peroxide, azobisisobutyronitrile, and cobalt acetylacetonate as initiators. The ease of addition of the monomer to the polymer follows the solubility of the monomer in the polymer film. No chemical interaction occurs between the PET film and the monomer; rather, the monomer is homopolymerized within the film and forms a semi-interpenetrating network so that the two homopolymers cannot be separated unless the PET matrix is destroyed. © 1995 John Wiley & Sons, Inc.     

Thermal and crystallization characteristics of poly(trimethylene terephthalate)/poly(ethylene naphthalate) blends

Poly(trimethylene terephthalate) (PTT)/poly(ethylene naphthalate) (PEN) blends were miscible in the amorphous state in all of the blend compositions studied, as evidenced by a single, composition-dependent glass transition temperature (T_g) observed for each blend composition. The variation in the T_g value with the blend composition was well predicted by the Gordon-Taylor equation, with the fitting parameter being 0.57. The cold-crystallization peak temperature decreased with increasing PTT content, while the melt-crystallization peak temperature decreased with increasing amount of the minor component. The subsequent melting behavior after both cold- and melt-crystallization exhibited melting point depression, in which the observed melting temperatures decreased with increasing amount of the minor component. During melt-crystallization, both components in the blends crystallized concurrently just to form their own crystals. The blend with 60% w/w of PTT exhibited the lowest total apparent degree of crystallinity.     

In situ preparation of poly(ethylene terephthalate)-SiO2 nanocomposites

Poly(ethylene terephthalate) (PET)/silica nanocomposites were synthesized by using the in situ polymerization approach. Sol-gel transformation based on the hydrolysis and condensation of tetraethoxysilane (TEOS) is used to prepare the inorganic phase, concurrent with condensation polymerization of terephthalic acid and ethylene glycol to produce the PET matrix. Due to the simultaneous formation of the polymer matrix and the inorganic networks, a macrophase separation is avoided, and the resulting materials have a high degree of homogeneity. The morphology and the crystallization behavior of the composites were examined by scanning electron microcopy (SEM) and differential scanning calorimetry (DSC), respectively.     

Structure and properties of new polyester elastomers composed of poly(trimethylene terephthalate) and poly(ethylene oxide)

Series of PTT-b-PEO copolymers with different composition of rigid PTT and PEO flexible segments were synthesized from dimethyl terephthalate (DMT), 1,3-propanediol (PDO), poly(ethylene glycol) (PEG, M_n = 1000 g/mol) in a two stage process involving transesterification and polycondensation in the melt. The weight fraction of flexible segments was varied between 20 and 70 wt%. The molecular structure of synthesized copolymers was confirmed by ¹H NMR and ¹³C NMR spectroscopy. The superstructure of these polymers was characterized by DSC, DMTA, WAXS and SAXS measurements. It was observed that domains of three types can exist in PTT-b-PEOT copolymers: semi-crystalline PTT, amorphous PEO rich phase (amorphous PEO/PTT blended phase) and semi-crystalline PEO phase. Semi-crystalline PEO phase was observed only at temperature below 0 °C for sample containing the highest concentration of PEO segment. The phase structure, thermal and mechanical properties are effected by copolymer composition. The copolymers containing 30÷70 wt% of PEO segment posses good thermoplastic elastomers properties with high thermal stability. Hardness and tensile strength rise with increase of PTT content in copolymers.     

结构改变对聚对苯二甲酸乙二醇酯局域能级性质的影响

用双轴拉伸、热处理和γ射线辐照的方法制备了一系列具有不同平面取向度,不同结晶度和不同分子链长度的PET试样。通过热释电极化温度扫描法分离出对解俘获电流峰贡献的各局域能级峰。平面取向度、结晶度和γ辐照剂量的提高引起局域能级深度增加,结构缺陷种类的增多导致局域能级数增大(由二个增至六个),能级深度分布加宽。     

Synthesis and hydrolytic degradation of poly(ethylene succinate) and poly(ethylene terephthalate) copolymers

The conditions of synthesis of statistical poly(ethylene succinate-co-terephthalate) copolymers (2GTS) and high molecular weight poly(ethylene succinate) (PES) with good hydrolytic and optical parameters, designed for the production of biodegradable products and resins, are presented in this article. Copolymers were prepared by melt polycondensation of bis-(β-hydroxyethylene terephthalate) (BHET) and succinic acid (SA) with excess of ethylene glycol (2G) in the presence of a novel titanium/silicate catalyst (C-94) and catalytic grade of germanium dioxide (GeO₂) as cocatalyst. The chemical structure and physical properties of those materials were characterized by ¹H NMR, FT-IR, dynamical-mechanical thermal analyses (DMTA), differential scanning calorimetry (DSC), solution viscosity and spectroscopic methods. The hydrolytic degradation was performed in a water solution with variable pH, also in garden soil and in compost. The highest hydrolytic degradation rate was observed for pH 4 and for compost. Better hydrolytic degradation values in compost medium were observed for copolyester prepared in the presence of GeO₂ as polycondensation cocatalyst. The copolyester with 40 mol% of aliphatic units was chosen for industrial syntheses which were performed in ELANA and subsequently the processing parameters and compatibility with potato starch of this polyester were checked by BIOP Biopolymer Technologies AG.     

Shape memory effects of poly(ethylene terephthalate-co-ethylene succinate) random copolymers

Random copolymers based on terephthalate acid, succinic acid and ethylene glycol, with thermally induced shape memory, were synthesized via melt polycondensation. The chemical structures of these poly(ethylene terephthalate-co-ethylene succinate) copolymers (PET-co-ES) were ascertained by ¹H NMR spectroscopy. The thermal and viscoelastic characteristics of these copolymers were studied in terms of the succinic acid content using differential scanning calorimetry and dynamic mechanical analysis. The shape memory effects of the copolymers were examined using the strain test. The experimental results suggested that all copolymers exhibited shape memory above the glass transition temperature and that the highest shape recovery rate was 90%. The shape recovery rates of all test samples declined with the number of cycles. This decrease in the shape recovery rate may result from the change in the degree of polymer orientation and/or crystallinity during repeated testing.     

Swelling-assisted modification of poly(ethylene terephthalate) by methacrylic acid

When a poly(ethylene terephthalate), PET, film is heated in an aqueous solution of methacrylic acid in the presence of hydrogen peroxide as an initiator, it is found that the weight of the film is increased. The amount of methacrylic acid that may be added onto the film is dependent upon the concentration of the monomer, the initiator, and the temperature at which the reaction occurs. Pretreatment of the film with 1,1,2,2,tetrachloroethane causes swelling and the amount of add-on is increased as the swelling level increases. Methacrylic-acid-modified PET films hydrolyze at room temperature in aqueous sodium hydroxide; the rate of hydrolysis is dependent upon the amount of add-on and the concentration of the base. This procedure leads to a chemically induced blend of polymethacrylic acid and poly(ethylene terephthalate), and grafting of the monomer onto the polymer film does not occur. © 1995 John Wiley & Sons, Inc.     

Transesterification of Ethylene Carbonate with Dimethyl Terephthalate over Various Metal Acetate Catalysts

IntroductionDimethyl carbonate(DMC) is known to be a novelbuilding block in organic synthesis. As an environmen-tally benign compound and a unique intermediate,DMC has attracted much attention[1,2]. Among the va-rious methods for synthesizing DMC, the tra…     

Iodine-Transfer Polymerization (ITP) of Ethylene and Copolymerization with Vinyl Acetate

Controlled radical polymerization of ethylene using different commercially available, cheap, and non-toxic iodo alkyls is performed by iodine transfer polymerization (ITP) under mild conditions (≤100 °C and ≤200 bar). The formed well-defined iodo end-capped polyethylene (PE−I) species is very stable upon storage. Narrow molar-mass distributions (dispersities around 1.6) were obtained up to number average molar masses of 7300 g mol⁻¹. The ethylene copolymerization by ITP (ITcoP) with vinyl acetate allowed to form a broad range of poly(ethylene-co-vinyl acetate) (EVA) containing from 0 to 85 mol % of VAc unit. In addition, EVA-b-PE block copolymers or EVA-b-EVA gradient block copolymers with different content of VAc in the blocks were obtained for the first time using ITP. Finally, reactivity trends were explored by a theoretical mechanistic study. This highly versatile synthetic platform provides a straightforward access to a diverse range of well-defined PE based polymer materials.     

Atom transfer radical polymerization of styrene from different poly(ethylene terephthalate) surfaces: Films, fibers and fabrics

Poly(ethylene terephthalate) (PET) is a semi-crystalline thermoplastic polyester used in many fields. For a variety of applications, however, it is necessary to impart desired properties by introducing specific functional groups on the surface. A simple method for growing polymer brushes by atom transfer radical polymerization (ATRP) on PET films, fibers and fabrics was devised. The different PET surfaces were first reacted with 1,2-diaminoethane by aminolysis reaction to incorporate primary amino and alcohol functions on the surface. Then, in a second step, ATRP initiator was grafted by reaction with bromoisobutyryl bromide. The efficiency of these reactions was confirmed by using colorimetric titration and X-ray photoelectron spectroscopy (XPS). Surface-initiated ATRP was performed in bulk using styrene monomer with CuBr/PMDETA catalytic system in the presence of a sacrificial initiator (ethyl 2-bromoisobutyrate). Good control of the polymerization was obtained as attested by comparison of polystyrene molar masses obtained in solution from sacrificial initiator with those obtained from the surface after cleavage. Wetting properties were found to vary systematically depending to the type of functionalization and grafting. Evolution of surface morphology according to reaction steps was investigated using atomic force microscopy (AFM).