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1.
A simple technique for the lamination of a conductive polymer film to an inert dielectric polymer film was demonstrated. The electrochemically synthesized and p‐toluenesulfonic acid‐doped polypyrrole (PPY) film was laminated simultaneously to the argon plasma‐pretreated PTFE film during the thermally induced graft copolymerization of the PTFE surface with a functional monomer. The graft copolymerization was carried out using glycidyl methacrylate (GMA) monomer containing 20% v/v hexamethyldiamine (HMDA) and in the absence of any polymerization initiator. Thermally induced graft copolymerization of the GMA monomer on the PPY surface was minimal. The lap shear and T‐peel adhesion strengths of the laminates were found to be dependent on the GMA graft concentration on the PTFE surface, which, in turn, was affected by the plasma pretreatment time of the film. To increase the GMA graft concentration for the enhancement of adhesion strength, the plasma‐pretreated PTFE surfaces were premodified via UV‐induced graft copolymerization with GMA prior to the simultaneous thermal graft copolymerization and lamination process. The modified surfaces and interfaces were characterized by X‐ray photoelectron spectroscopy (XPS). Through XPS measurements of the delaminated surfaces, it was found that the PPY/PTFE laminates failed predominantly by cohesive failure inside the PTFE substrate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 716–727, 2001  相似文献   

2.
The steady‐state fluorescence (SSF) technique was used to study the polymerization rate in free‐radical crosslinking copolymerization (FCC) of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM). Pyrene (Py) was used as a fluorescent probe for the in situ polymerization experiments. The increase in Py intensity was monitored during FCC. The Stern–Volmer kinetic was employed to determine the MMA consumption rate during gelation process for various EGDM contents and at different temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1907–1913, 2001  相似文献   

3.
To improve the moisture sorption property of nylon‐6,6 film, ally pentafluorobenzene (APFB) was incorporated on the argon plasma‐pretreated nylon film by UV or thermally induced surface graft copolymerzation. The plasma pretreatment introduced peroxides that were degraded into radicals to initiate the graft copolymerization of APFB on the nylon surface. The modified surfaces were characterized by X‐ray photoelectron spectroscopy (XPS) and contact angle measurement. The moisture sorption was assessed by the coulometric test method. The efficiency of surface graft copolymerization was affected by plasma pretreatment time of the nylon substrate, as well as by the UV or thermal graft copolymerization time. The UV graft‐copolymerized nylon film exhibited a significantly lower extent of moisture sorption when compared to that of the pristine films, even at low graft concentration. However, the moisture sorption behavior for the thermally graft copolymerized films was similar to that of the pristine films. Contact angle and XPS measurements suggested that the reduction in moisture sorption for the UV graft‐copolymerized nylon‐6,6 film was attributable to the fact that the hydrophobic polymer layer was formed on the nylon surface, and the hydrophobic layer of an appropriate thickness could serve as an effective barrier to moisture. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1366–1373, 2000  相似文献   

4.
The grafting of the methyl methacrylate (MMA) monomer onto natural rubber using potassium persulfate as an initiator was carried out by emulsion polymerization. The rubber macroradicals reacted with MMA to form graft copolymers. The morphology of grafted natural rubber (GNR) was determined by transmission electron microscopy and it was confirmed that the graft copolymerization was a surface‐controlled process. The effects of the initiator concentration, reaction temperature, monomer concentration, and reaction time on the monomer conversion and grafting efficiency were investigated. The grafting efficiency of the GNR was determined by a solvent‐extraction technique. The natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) (NR‐g‐MMA/PMMA) blends were prepared by a melt‐mixing system. The mechanical properties and the fracture behavior of GNR/PMMA blends were evaluated as a function of the graft copolymer composition and the blend ratio. The tensile strength, tear strength, and hardness increased with an increase in PMMA content. The tensile fracture surface examined by scanning electron microscopy disclosed that the graft copolymer acted as an interfacial agent and gave a good adhesion between the two phases of the compatibilized blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 428–439, 2001  相似文献   

5.
Surface modifications of pristine and ozone-pretreated low-density polyethylene (LDPE) films were carried out via UV-induced graft copolymerization with a photoinitiator-containing, epoxy-based commercial monomer (DuPont Somos? 6100 for solid imaging and optical lithography) and also with the photoinitiator-free acrylic acid (AAc). The chemical composition and microstructure of the graft copolymerized surfaces were studied by angle-resolved X-ray photoelectron spectroscopy (XPS). The concentration of surface grafted polymer increased with the UV illumination time and the monomer concentration. For LDPE films graft copolymerized with the epoxy-based monomer, surface chain rearrangement was not observed or was less well pronounced, due to the partial crosslinking of the grafted chains. Simultaneous photografting and photolamination between two LDPE films, or between a LDPE film and a poly(ethylene terephthalate) (PET) film, in the presence of either monomer system, were also investigated. The photolamination rates and strengths depend on the ozone pretreatment time, the UV illumination time, and the UV wavelength, as well as on the nature of the substrate materials. A shear adhesion strength approaching 150 N/cm2 could be achieved with either monomer system, provided that the polymer films were pretreated with ozone. The failure mode of the photolaminated surfaces was cohesive in nature in the case of the photoinitiator-containing epoxy monomer, but was either cohesive or adhesional in nature (depending on the substrate assembly) in the case of the photoinitiator-free AAc monomer.  相似文献   

6.
Atom transfer radical polymerization has been applied to simultaneously copolymerize methyl methacrylate (MMA) and N‐cyclohexylmaleimide (NCMI). Molecular weight behaviour and kinetic study on the copolymerization with the CuBr/bipyridine(bpy) catalyst system in anisole indicate that MMA/NCMI copolymerization behaves in a ‘living’ fashion. The influence of several factors, such as temperature, solvent, initiator and monomer ratio, on the copolymerization were investigated. Copolymerization of MMA and NCMI in the presence of CuBr/bpy using cyclohexanone as a solvent instead of anisole displayed poor control. The monomer reactivity ratios were evaluated as rNCMI = 0.26 and rMMA=1.35. The glass transition temperature of the resulting copolymer increases with increasing NCMI concentration. The thermal stability of plexiglass could be improved through copolymerization with NCMI. © 2000 Society of Chemical Industry  相似文献   

7.
Electroless plating of copper via a tin‐free activation process was carried out effectively on two types of fluorinated polyimide (FPI) films modified by UV‐induced surface graft copolymerization with N‐containing monomers, such as 1‐vinylimidazole (VIDz) and 4‐vinyl pyridine (4VP). The graft copolymerization of VIDz and 4VP was carried out on the argon (Ar) plasma‐pretreated FPI films via a solvent‐free process under atmospheric conditions. X‐ray photoelectron spectroscopy (XPS) results showed that the VIDz graft‐copolymerized FPI surface (the VIDz‐g‐FPI surface) and 4VP graft‐copolymerized FPI surface (the 4VP‐g‐FPI surface) were much more susceptible to the electroless deposition of metals via the Sn‐free process than the pristine FPI surfaces, and the FPI surfaces modified by Ar plasma pretreatment alone. T‐peel adhesion strengths above 9 N/cm were achieved for the electrolessly deposited copper on both VIDz‐g‐FPI surfaces (the Cu/VIDz‐g‐FPI assemblies) and 4VP‐g‐FPI surfaces (the Cu/4VP‐g‐FPI assemblies). These adhesion strength values were much higher than those obtained for assemblies involving electrolessly deposited copper on pristine or on Ar plasma pretreated FPI films. The high adhesion strength of the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies was attributed to the synergistic effect of spatial interactions of the grafted VIDz or 4VP polymer chains with the copper atoms, and the fact that the VIDz or 4VP polymer chains were covalently tethered on the FPI surfaces. XPS results also revealed that the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies delaminated by cohesive failure inside the FPI films.  相似文献   

8.
Ozone‐induced grafting was developed to improve the hemocompatibility of biomaterials based on low‐density polyethylene (LDPE). An LDPE film was activated with ozone and graft‐polymerized with N,N′‐dimethyl(methacryloylethyl)ammonium propane sulfonate (DMAPS). The existence of sulfobetaine structures on the grafted film was confirmed by X‐ray photoelectron spectroscopy and attenuated total reflection/Fourier transform infrared (ATR–FTIR). More DMAPS was grafted onto the LDPE film as the DMAPS concentration increased, as determined by ATR–FTIR. Static contact‐angle measurements indicated that the DMAPS‐grafted LDPE film had a significant increase in hydrophilicity. The blood compatibility of the grafted film was preliminarily evaluated with a platelet‐rich‐plasma (PRP) adhesion study. No platelet adhesion was observed on the grafted film incubated with PRP at 37°C for 180 min. This new sulfoammonium zwitterionic‐structure‐grafted biomaterial might have potential for biomedical applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3697–3703, 2006  相似文献   

9.
Copolymerization of styrene (St) and methyl methacrylate (MMA) was carried out using 1,1,2,2‐tetraphenyl‐1,2‐bis (trimethylsilyloxy) ethane (TPSE) as initiator; the copolymerization proceeded via a “living” radical mechanism and the polymer molecular weight (Mw) increased with the conversion and polymerization time. The reactivity ratios for TPSE and azobisisobutyronitrile (AIBN) systems calculated by Finemann–Ross method were rSt = 0.216 ± 0.003, rMMA= 0.403 ± 0.01 for the former and rSt= 0.52 ± 0.01, rMMA= 0.46 ± 0.01 for the latter, respectively, and the difference between them and the effect of polymerization conditions on copolymerization are discussed. Thermal analysis proved that the copolymers obtained by TPSE system showed higher sequence regularity than that obtained by the AIBN system, and the sequence regularity increased with the content of styrene in copolymer chain segment. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1474–1482, 2001  相似文献   

10.
The preirradiation method of grafting has been established by ultraviolet radiation. Methyl methacrylate (MMA) was grafted onto jute fiber in an aqueous medium. The variation of graft weight with UV‐radiation time, monomer concentration, and reaction time was investigated. The conversion of monomer into homopolymer and graft copolymer was evaluated. The graft weight passes through a maximum value (~ 122%) with UV‐radiation time. The optimum value of the monomer concentration was evaluated for maximum degree of grafting. Graft copolymerization of MMA onto lignocellulose fiber significantly increases the elongation at break (~ 65%) compared to that of the “as‐received” sample. However, a linear decrease on breaking load was observed with the increase of graft weight. The estimation of degree of grafting was achieved using an IR technique by correlating band intensities with the degree of grafting. Considering the water‐absorption property, the grafted sample showed a maximum up to 61% decrease in hydrophilicity compared to that of the as‐received sample. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1667–1675, 2004  相似文献   

11.
Surface modification of Ar plasma‐pretreated high density polyethylene (HDPE) film via UV‐induced graft copolymerization with glycidyl methacrylate (GMA) and 2‐hydroxyethylacrylate (HEA) was carried out to improve the adhesion with evaporated copper. The surface compositions of the modified HDPE surfaces were characterized by X‐ray photoelectron spectroscopy (XPS). The adhesion strengths of evaporated copper with the graft‐copolymerized HDPE films were affected by the Ar plasma pretreatment time, the monomer concentration used for graft copolymerization, and the graft concentration. Post‐treatments, such as plasma post‐treatments after graft copolymerization and thermal treatment (curing) after metalization, further enhanced the adhesion strength of the Cu/HDPE laminates. The T‐type peel strengths of the laminates involving the graft‐modified and plasma posttreated HDPE films were greater than 15 N/cm. The enhanced adhesion strength resulted from the strong affinity of the graft chains for Cu and the fact that the graft chains were covalently tethered on the HDPE surface. XPS characterization of the delaminated surfaces of the Cu/HDPE laminates revealed that the failure mode of the laminates with T‐peel adhesion strengths greater than 5 N/cm was cohesive in nature.  相似文献   

12.
The graft copolymerizations of N‐vinylpyrrolidione(NVP) onto ethylene–propylene–diene terpolymer (EPDM) were carried out with benzoyl peroxide (BPO) as an initiator in toluene. The synthesized EPDM‐g‐NVP (ENVP) was characterized by infrared (IR) spectroscopy and gel permeation chromatography (GPC). The effects of initiator and monomer concentrations, reaction time, and temperature were investigated in the graft copolymerization. The highest graft efficiency was obtained at 0.04 mol of NVP, 2 g of EPDM, 2 wt % of BPO and 80°C for 72 h. Modified ENVP (MENVP) was obtained by the reaction of ENVP and KOH in MeOH. Properties of EPDM, ENVP, and MENVP were investigated by a thermogravimetric analyzer (TGA), an instron tensile tester, a Fade‐O‐Meter, and a UV spectrophotometer. Tensile strength and light resistance of ENVP were better than those of MENVP. The dyeability of polymers was increased in following order: MENVP > ENVP > EPDM. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1177–1184, 1999  相似文献   

13.
In view of the complexity of surface photografting polymerization of vinyl acetate/maleic anhydride (VAC/MAH) binary monomer systems, a novel method was adopted in the present article to obtain insight into the relevant grafting copolymerization mechanism. This method includes two steps: semibenzopinacol dormant groups were first introduced onto LDPE film by UV‐irradiation and then thermally reactivated to produce LDPE macromolecular free radicals, which initiated the grafting copolymerization of VAC and MAH. It was demonstrated that, in the first step, the solvent used to introduce benzophenone (BP) to LDPE film largely affected the subsequent grafting copolymerization, which was closely related to the affinity of the solvent toward the substrate. The monomer feed composition had considerable influence on both the grafting and nongrafting copolymerization; however, the maximum copolymerization rates did not appear in the polymerization system with [VAC]/[MAH] being 1 : 1, but, in the system with a bit more VAC than MAH, as the total monomer concentration was raised, the maximum copolymerization rates tended to appear in the system with [VAC] equal to [MAH]. The relationship between the total copolymerization rate (RP) and monomer concentration was determined to be LnRP ∝ [VAC + MAH]1.83. All of these results indicated that both charge transfer (CT) complex formed by VAC and MAH and free monomers took part in grafting copolymerization. This feature differentiated the surface grafting copolymerization of VAC/MAH from the well‐studied thermally induced alternating copolymerization of VAC/MAH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

14.
The corona discharge technique was explored as a means of forming chemically active sites on a low‐density polyethylene (LDPE) film surface. The active species thus prepared at atmospheric pressure in air was exploited to subsequently induce copolymerization of 2‐hydroxyethyl methacrylate (HEMA) onto LDPE film in aqueous solution. The results showed that with the corona discharge voltage, reaction temperature, and inhibitor concentration in the reaction solution the grafting degree increased to a maximum and then decreased. As the corona discharge time, reaction time, and HEMA concentration in the reaction solution increased, the grafting degree increased. With reaction conditions of a 5 vol % HEMA concentration, 50°C copolymerization temperature, and a 2.0‐h reaction time, the degree of grafting of the LDPE film reached a high value of 158.0 μg/cm2 after treatment for 72 s with a 15‐kV voltage at 50 Hz. Some characteristic peaks of the grafted LDPE came into view at 1719 cm?1 on attenuated total reflectance IR spectra (C?O in ester groups) and at 531 eV on electron spectroscopy for chemical analysis (ESCA) spectra (O1s). The C1s core level ESCA spectrum of HEMA‐grafted LDPE showed two strong peaks at ~286.6 eV (? C ? O? from hydroxyl groups and ester groups) and ~289.1 eV (O?C ? O? from ester groups), and the C atom ratio in the ? C? O? groups and O?C? O groups was 2:1. The hydrophilicity of the grafted LDPE film was remarkably improved compared to that of the ungrafted LDPE film. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2881–2887, 2001  相似文献   

15.
A graft copolymer of oleic acid (OA) onto low‐density polyethylene (LDPE) was prepared using dicumyl peroxide (DCP) as an initiator in the molten state. The grafting was carried out in a Haake rheometer. The effects of the reaction time and the amount of DCP and the monomer on the percentage of grafting were studied. The rheological behavior and the melt‐flow rate of the graft copolymer (LDPE‐g‐OA) were also investigated. FTIR spectroscopy and a mass spectrum were used to characterize the structure of LDPE‐g‐OA. The experimental results showed that when the OA amount was 10 wt % and the DCP amount was 0.4 wt % based on the LDPE the percentage of grafting of LDPE‐g‐OA, prepared by maintaining the temperature at 170°C and the roller speed at 80 rpm, was about 6 wt %. It was found that both LDPE and LDPE‐g‐OA were pseudoplastic fluids. OA was grafted onto LDPE in the form of a monomer and a dimer. The grafted LDPE is expected to act as a compatibilizer between starch and polyethylene. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3299–3304, 2003  相似文献   

16.
Blood filtration requires a high removal ratio of leukocytes and with simultaneous high recovery ratio of platelets and other beneficial components. Problems are often encountered with blood filter materials in terms of high platelet loss. Zwitterions such as phosphorylcholine, sulfobetaine and carboxybetaine show effective resistance against protein adsorption and platelet adhesion. The study reported was aimed at achieving surface modification of poly(butylene terephthalate) non‐woven fabric (PBTNF) using UV radiation‐induced graft copolymerization of a zwitterionic sulfobetaine, N‐(3‐sulfopropyl)‐N‐methacroyloxyethyl‐N,N‐dimethylammonium betaine (SMDB), in order to improve the wettability and platelet recovery ratio of the PBTNF. Attenuated total reflection Fourier transform infrared and X‐ray photoelectron spectroscopy results showed that SMDB was successfully grafted onto the PBTNF. Photoinitiator concentration, monomer concentration and UV irradiation time affected markedly the degree of grafting. Critical wetting surface tension, water wetting time and hemolysis tests showed an improvement in wettability and blood compatibility as a result of graft copolymerization of SMDB. A blood filter material composed of SMDB‐modified PBTNF reduced platelet adhesion and had higher platelet recovery compared to poly(acrylic acid)‐modified PBTNF. It was found that SMDB monomer was successfully grafted onto PBTNF using UV radiation. The degree of grafting of SMDB could be controlled by varying the photoinitiator concentration, monomer concentration and UV irradiation time. SMDB‐modified PBTNF showed significant improvement in wettability and blood compatibility. The zwitterionic structure of SMDB is resistant to platelet adhesion. The SMDB‐modified PBTNF could be a candidate for a blood filter material and in other medical applications. Copyright © 2010 Society of Chemical Industry  相似文献   

17.
A novel monomer, 2‐methyl‐acrylic acid 2‐(3‐isocyanato‐2‐methyl‐phenyl carbamoyloxy)‐ethyl ester (HT), was synthesized by the reaction of 2‐hydroxymethyl methacrylate with toluene diisocyanate. The influences of solvents, temperature and catalyst, dibutyl tin dilaurate on the total yield of HT were investigated and theoptimum synthesis conditions were obtained. The obtained monomer was then used to modify low density polyethylene (LDPE) in the Haake Rheomix 600P via melt grafting copolymerization. The modified LDPE was characterized by Fourier transform infrared. During the grafting process, single‐step and two‐step procedures were compared and the results showed that the two‐step procedure was more favorable. In a two‐step procedure, the influences of melting temperatures, monomer amount, and ethylene vinyl acetate copolymer (EVA, Mn = 800–1200) on the graft degree were also investigated. The investigation confirmed that EVA acting as a dispersant could enhance the dispersion of the monomer and improve graft degree significantly, and net value of increased graft degree was about 1.5%. The better dispersion of HT in the matrix of LDPE was confirmed via scanning electron microscope after adding EVA to the system. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers  相似文献   

18.
The graft copolymerization of methyl methacrylate (MMA) onto chitosan was tried via a new protection‐graft‐deprotection procedure. Because the intermediate phthaloylchitosan was soluble in organic solvents, the graft copolymerization was carried out in a homogeneous system. Grafting was initiated by γ‐irradiation. The graft percentage extent was dependent on the irradiation dose and the concentration of MMA monomer, and copolymers with grafting above 100 % were readily prepared. The graft copolymers exhibited a high affinity not only for aqueous acid but also for some organic solvents. Differential scanning calorimetry measurements revealed the presence of a glass transition phenomenon, which could be ascribed to the poly(methyl methacrylate) side‐chains. Copyright © 2004 Society of Chemical Industry  相似文献   

19.
Modification of poly(tetrafluoroethylene‐co‐ethylene), Tefzel (ETFE), film has been carried out by grafting methylmethacrylate (MMA) by radiation method including preirradiation and double‐irradiation methods. Percentage of grafting has been determined as a function of the (i) total dose, (ii) monomer concentration, (iii) amount of liquor ratio, (iv) reaction time, and (v) temperature.The effect of different alcohols such as methanol, ethanol, 2‐propanol, n‐butanol, n‐pentanol, and 2‐ethoxy ethanol on percentage of grafting of MMA was also studied. The graft copolymers were characterized by IR spectroscopy and thermogravimetric analysis (TGA). Methylmethacrylate produces higher percentage of grafting by preirradiaton method than double‐irradiation method. MMA‐grafted ETFE films (Sirr), i.e., prepared by preirradiation involving single irradiation show better thermal stability than MMA‐grafted ETFE films (Dirr), i.e., prepared by double irradiation and unmodified ETFE film. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

20.
Surface‐modified polypropylene (PP) films with thermally and photochemically sensitive copolymers consisting of N‐(2‐hydroxypropyl)methacrylamide (HPMA) and 4‐(4‐methoxyphenylazo)phenyl methacrylate (MPAP), poly(HPMA‐co‐MPAP)‐g‐PP (abbreviated g‐PP) film, were prepared by graft copolymerization with an Ar‐plasma postpolymerization technique. The surfaces of the g‐PP films were characterized by means of X‐ray photoelectron spectroscopy; the percentage grafting of poly(HPMA‐co‐MPAP) with a number‐average molecular weight of 3.28 × 104 was 7.12%, and the molar ratio of HPMA–MPAH in the copolymer was 0.75:0.25. The stimuli‐sensitive adsorption of albumin and polystyrene microspheres on the g‐PP film was also measured. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 143–148, 2003  相似文献   

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