Graft copolymerization of methacrylic acid and acrylamide onto acrylonitrile-butadiene-styrene terpolymer by photoinduced hydroperoxide

Graft copolymerization of methacrylic acid (MAA) or acrylamide (AM) from an aqueous solution onto acrylonitrile-butadiene-styrene terpolymer (ABS) was initiated by the thermal decomposition of polymeric hydroperoxides, which are formed upon UV irradiationof ABS, which contains anthracene. Diffusion of anthracene at room temperature from a methanolic solution into ABS was affected by the acrylonitrile content ofABS.The graft yield was independent on the concentration of anthracene in the wide range of 0.03 X 10^-3 to 14.29 X 10^?3 mol/L in ABS. The graft polymerization reaction does not occur below 100°C.The effect of other variables, such as time of irradiation, intensity of UV, reaction time, and concentration of monomer in aqueous solution, on the amount of monomer grafted to ABS were also investigated.The contact angle significantly decreases upon grafting, indicating that the graft layer is on the surface of the polymer. © 1995 John Wiley & Sons, Inc.     

Some features of electrochemically initiated copolymerization of acrylic acid and acrylamide

Some features of the electrocopolymerization of acrylic acid and acrylamide in aqueous ammonium persulfate have been studied. UV spectroscopic and polarographic data attest to the intermolecular interaction of acrylic acid with acrylamide with the formation of 31, 32, and 11 complexes; the former complex is the strongest. Electrochemical initiation of polymerization of monomers whose _1/2 differ by 0.3 V can result in a copoiymer. The composition of the cathode polymeric coating has been determined by IR-spectroscopy and elemental analysis data. The molar ratios of acrylic acid to acrylamide in this coating and in the complex of the monomers are identical. The role of these complexes as elementary units in copolymerization is noted.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 250–254, February, 1994.     

电火花引发丙烯酰胺接枝BOPP薄膜的研究

采用FT-IR,ESCA,试样与水接触角和接枝率的测定探索了电火花用于引发丙烯酰胺(AAM)在BOPP薄膜表面接枝聚合反应的方法,研究了接枝BOPP薄膜的表面结构和亲水性能。结果表明,电火花能有效地引发AAM在BOPP薄膜表面的接枝聚合反应,随着电火花处理时间和接枝反应时间的延长,AAM在BOPP薄膜表面的接枝率增大。电火花处理10min,BOPP薄膜在70℃,20%(质量分数)的AAM水溶液中反应1h,接枝率高达2.06%。接枝后BOPP薄膜与水的接触角显著下降,亲水性能得到明显改善。     

Functionalization of polyethylene surface using plasma-induced graft copolymerization of acrylic acid

Plasma-induced graft copolymerization of acrylic acid onto PE films was investigated. The influence of plasma treatment power, pressure, time, graft copolymerization time, and monomer concentration on polymerization yield was determined. A chemical shift of the Cls signal of Ar plasma treated and untreated PE films was revealed by ESCA, which also verified the presence of grafted PAAc. An increase in graft polymerization yield with plasma treatment time and power was found. Both the plasma treated film and the subsequently grafted film were shown to be hydrophilic. Only the grafted film, however, shows an invariably low contact angle. The decomposition of peroxides upon heating was followed by a simple first-order reaction. © 1993 John Wiley & Sons, Inc.     

Potassium diperiodatonickelate‐initiated graft copolymerization of methyl acrylate onto organophilic montmorillonite

Using potassium diperiodatonickelate (Ni (IV)) as an efficient initiator, the graft copolymerization of methyl acrylate (MA) onto organophilic montmorillonite (OMMT) was successfully performed in an alkaline medium. Three grafting parameters were systematically evaluated as functions of the temperature, the initiator concentration, reaction time, pH value, and the ratio of MA to OMMT substrate. The structure of the titled graft copolymers (OMMT‐g‐PMA) were confirmed by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermo‐gravimetric analysis (TGA). It was found that Ni (IV) was a highly efficient initiator for graft copolymerization of the MA onto OMMT, i.e., grafting efficiency is as high as 95% and grafting percentage can be facilely controlled within 700% in this study. In addition, the highest grafting efficiency and grafting percentage were obtained when temperature adopted was over 40°C and pH was about 10.3. A single‐electron‐transfer mechanism was proposed to illustrate the formation of radicals and the initiation reaction. Copyright © 2008 John Wiley & Sons, Ltd.     

丙烯酸与纤维素在60Co辐照下的接枝聚合反应

高吸水性树脂是一类高分子功能材料，吸水量大、保水性强，可以吸收比自身重量高几百到几千倍的水，而且所吸人的水在适当的压力下也不会被挤出。60年代初美国最早开始淀粉接枝丙烯腈研究，随后国内外学者又用纤维素或其衍生物与丙烯腈、丙烯酸酯等单体接枝聚合，经碱液水解后而得。纤维素类高吸水树脂虽然吸水倍率不很高，但吸水速度较快，吸水后形成的凝胶强度较大，其单体制备严格条件下，纤维素要经过活化，要有引发剂诱导，还要通氮气，在一定温度下反应才能进行。本文采用纤维素与丙烯酸在常温和辐照条件下，无需活化、引发剂和氮气保护，即可进行接枝聚合而制备高吸水材料。     

Oxidation of polyethylene surface by glow discharge and subsequent graft copolymerization of acrylic acid

Plasma-induced graft copolymerization of acrylic acid, which was incorporated into PE films, was investigated here. The influence of plasma conditions such as plasma treatment gases, power, pressure, time, monomer concentration, and graft copolymerization time on polymerization yield was determined. The samples were characterized by ESCA, IR, and water contact angle. A respective chemical shift of the C1s signal of Ar or O₂ plasmatreated and untreated PE films was revealed by ESCA, in which the presence of the grafted PAAc was also verified. An increase in polymerization yield with plasma treatment duration and power was found. That the grafted copolymerization was limited to a very thin surface region was revealed by optical microscopy on the cross section of the grafted film. © 1993 John Wiley & Sons, Inc.     

Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. I. Kinetic study on the grafting onto poly(tetrafluoroethylene-ethylene) copolymer

Direct radiation-induced grafting of aqueous acrylic acid (AAc) onto poly(tetrafluoroethylene-ethylene) (ET) film has been studied. The effect of grafting conditions such as monomer concentration, exposure dose, dose rate, and film thickness on the grafting yield was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.2 order. The dependence of the grafting rate on dose rate was found to be 0.6 order regardless of the film thickness. The relationship between the grafting rate and film thickness gave a negative first-order dependence. The results suggest that the grafting process is mainly controlled by monomer diffusion, and it was concluded that this grafting system proceeded by the front mechanism. The swelling behavior increases linearly with degree of grafting. The electrical conductivity and mechanical properties for the trunk and grafted polymer were investigated at different irradiation doses in air and under vacuum irradiations. © 1992 John Wiley & Sons, Inc.     

Graft copolymerization of methyl acrylate onto potato starch initiated by ceric ammonium nitrate

A study was made of the ceric ammonium nitrate (CAN) initiated graft copolymerization of methyl acrylate (MA) onto potato starch. The variables affecting the graft were investigated. The optimums have been obtained; they are the concentrations of MA, CAN, and nitric acid (HNO₃) (1.08, 5.0 × 10^?3, and 0.081 mol/L, respectively). The reaction temperature is ca. 50°C and the reaction time is 2 h. The molecular weight of grafted poly(methylacrylate) has been determined. On the basis of experimental results, the mechanism of grafting has been explored, a new kinetic equation of the graft copolymerization is established: R_p = Kk_d [STOH] [Ce⁴⁺] + Kk_pk_d/k_t[STOH][M], where K, k_d, k_p, and k_t are constants. The equation fits the results of experiments. © 1993 John Wiley & Sons, Inc.     

Frontal copolymerization synthesis and property characterization of starch-graft-poly(acrylic acid) hydrogels

Recently, a considerable amount of research has centered on uniquely structured polymers synthesized through self-propagating frontal polymerization. The obtained polymer materials have better features than those obtained by using the classical batch route. The additional advantages are short reaction times and low cost. This work describes the first frontal polymerization synthesis of a graft copolymer superabsorbent hydrogel of acrylic acid onto starch at high monomer and initiator concentration. The effects of varying the relative amounts of the reaction components on the most relevant parameters relating to frontal polymerization were explored. The front velocity dependence on initiator concentration could be fit to a power function. The temperature profiles were found to be very sharp with a maximum temperature below 150 degrees C, which was responsible for high monomer conversion. The ultimate properties of the product appear to depend on the polymerization front velocity and the temperature. The high-temperature and rapid temperature increase at the polymerization front led to products with interconnected porous structures caused by the evaporation of water. So, a fast-swelling, highly absorbing hydrogel with respect to batch polymerization was obtained.     

Kinetics and mechanism of grafting of undecylenic acid onto acrylonitrile–butadiene–styrene terpolymer

The graft copolymerization of undecylenic acid onto acrylonitrile–butadiene–styrene terpolymer (ABS) was initiated with benzoyl peroxide (BPO) in a 1,2‐dichloroethane solution. IR spectra confirmed that undecylenic acid was successfully grafted onto the ABS backbone. The influence of the concentrations of undecylenic acid, BPO, and ABS on the graft copolymerization was studied. A reaction mechanism was proposed: the grafting most likely took place through the addition of poly(undecylenic acid) radicals to the double bond of the butadiene region of ABS. A monomer cage effect on the graft reaction was observed to depend on the 1.5 power of the monomer concentration from the experimental results of the initial rate of graft copolymerization. The initial rate of graft copolymerization was written as R_p = 1.77 × 10⁻³[P][I₂][M]^2.5/([P]+2.75[M]^2.5)². © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 486–494, 2001     

Preparation of poly(ε-caprolactone)-co-poly(acrylic acid) by radiation-induced grafting

Acrylic acid was grafted onto poly(ε-caprolactone) (PCL) films by using electron beam (EB) preirradiation technique. The effect of reaction time, monomer concentration, radiation dose, time between irradiation and grafting, radiation atmosphere, and polymer crystallinity on the extent of grafting were studied. Silver and tin ions were attached to the grafted chains in order to study the grafting process. The irradiation in air was initially more rapid, but the final extent of grafting was the same when irradiated in nitrogen atmosphere. Maximum grafting extents exceeding 400% could be obtained. The optimal grafting was obtained at an acrylic acid to water ratio of 30 : 70. The grafting process could be initiated at a dose as low as 12 kGy. The grafting process proved to start at the surface and was extended into the bulk with time. The ability to form crystals was reduced as the grafting extent increased. The water uptake of the poly(ε-caprolactone)-graft-poly(acrylic acid) was increasing with increasing grafting extent, but reached a maximum of ca 100% for all grafting extents above 85%. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1805–1812, 1998     

Novel emulsion graft copolymerization onto the silylmethyl group of poly(dimethylsiloxane)

The influence of radical initiators upon the emulsion graft copolymerization of styrene and acrylonitrile onto poly(dimethylsiloxane) (PDMS) was studied. As initiators, a series of peroxides and hydroperoxides were coupled with ferrous sulfate, among which the tert-butyl peroxylaurate system gave the highest grafting efficiency (30%). The tert-butyl peroxylaurate initiator fulfills the criteria for efficient radical grafting by generating only the tert-butoxy radical, which is reluctant to form a carbon radical via β-scission, being highly hydrophobic, and not carrying a tertiary hydrogen that may be abstracted by a radical. ¹³C-NMR analysis of the products showed that the grafting occurred on the silylmethyl groups of PDMS to give 10–25 grafts per polymer and graft ratio in the range 44–140%. The PDMS graft copolymers thus obtained could be used as surface-modifying agents to improve the lubricity and water-repellency of ABS [poly(styrene-co-acrylonitrile)-graft-polybutadiene]. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2607–2617, 1997     

Photo-grafting Poly(acrylic acid) onto Poly(lactic acid) Chains in Solution

Poly(lactic acid)(PLA)is one of the most important bio-plastics,and chemical modification of the already-polymerized poly(lactic acid)chains may enable optimization of its material properties and expand its application areas.In this study,we demonstrated that poly(lactic acid)can be readily dissolved in acrylic acid at room temperature,and acrylic acid can be graft-polymerized onto poly(lactic acid)chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet(UV)irradiation.Similar photo-grafting polymerization of acrylic acid(PAA)has only been studied before in the surface modification of polymer films.The graft ratio could be controlled by various reaction parameters,including irradiation time,benzophenone content,and monomer/polymer ratios.This photo-grafting reaction resulted in high graft ratio(graft ratio PAA/PLA up to 180%)without formation of homopolymers of acrylic acid.When the PAA/PLA graft ratio was higher than 100%,the resulting PLA-g-PAA polymer was found dispersible in water.The pros and cons of the photo-grafting reaction were also discussed.     

Optimal estimation of reactivity ratios for acrylamide/acrylic acid copolymerization

Reactivity ratios for the important acrylamide (AAm)/acrylic acid (AAc) copolymerization system exhibit considerable scatter in previously published literature, and therefore, there is a need for more definitive values for these reactivity ratios. An appropriate methodology, based on the error‐in‐variables‐model (EVM) framework along with a direct numerical integration procedure, is applied in order to determine reliable reactivity ratios. The reliability of the results is confirmed with extensive and independent replication. Furthermore, via an EVM‐based criterion for the design of experiments using mechanistic models, optimal feed compositions are calculated, and from these optimal reactivity ratios are estimated for the first time (r_AAm = 1.33 and r_AAc = 0.23) based on information from the full conversion range. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4819–4827     

悬浮法合成聚丙烯接枝丙烯酸

用过氧化二苯甲酰作引发剂以水相悬浮法合成聚丙烯接枝丙烯酸。通过反应条件、组分等因素对PP的接枝率和接枝效率的影响研究,确定较佳配比工艺条件：溶用莳8-0min;反应温度90℃;反应时间90min;在氮气气氛中,丙烯酸7％;过氧化二苯甲酰3．3％;二甲苯25％;水和聚丙烯的重量比为3：1;若加入适量催化剂（1－1．7％0异氰尿酸三烯丙酯能显著提高接枝率。用此PP－g-AA作CaCO3、PP/PA6和合物的相容剂,材料的力学性能有很大的提高。     

木薯淀粉与丙烯酸接枝共聚制备淀粉增稠剂

用过硫酸盐 (过硫酸纳、钾或胺盐 )氧化法使木薯淀粉与丙烯酸接枝共聚。探索到最佳反应温度 55℃ ,反应时间 3h ,单体用量 3.1 2 5mol/L ,引发剂浓度 3.5mmol/L ,接枝百分率可达 70 %以上。产品用作淀粉糊的增稠起到明显的效果     

Influence of mechanical activation on the graft copolymerization of sugarcane bagasse and acrylic acid

Sugarcane bagasse (SCB) was mechanically activated by home-made high efficiency stirring mill. Graft copolymers (SCB-g-PAA) of SCB with different mechanical activation times (t_M) and acrylic acid (AA) have been synthesized by using ammonium persulfate/sodium sulfite redox pair as an initiator in aqueous solution. The effect of t_M on the graft co-polymerization was evaluated by grafting ratio (GR) and grafting efficiency (GE). In addition, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the granular morphology, functional groups, crystal structure and thermal properties of the product. It was found that the mechanical activation could split fiber bundles and decrease significantly the crystallinity. SCB degraded after the mechanical activation (MA) and its thermal stability declined. Moreover, the graft copolymerization was enhanced obviously by MA processing. And GR and GE increased with the increase of activation time.     

Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. II. Graft copolymer–metal complexes obtained by radiation grafting onto poly(tetrafluoroethylene-ethylene) copolymer

A study has been made on the graft copolymers obtained by radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene-ethylene) (ET) films. The conversion of the graft copolymer into metal acrylate copolymer complex was carried out by treatment with different metal salts. Such a prepared graft copolymer–metal complex was confirmed by different methods: IR, UV spectrometry, degree of coloration, and x-ray fluorescence. Some selected properties of the graft copolymer–metal complexes such as electrical conductivity, swelling behavior, and mechanical properties were investigated. The influence of metal complexes in the graft copolymers was determined and compared with the grafted films. The possibility of the practical uses for such prepared graft copolymer–metal complexes was discussed and determined. It was assumed that such materials may be of great interest in the field of semiconducting materials in addition to their applicability as cation-exchange membranes. © 1993 John Wiley & Sons, Inc.     

Modified carrageenan 3. Synthesis of a novel polysaccharide-based superabsorbent hydrogel via graft copolymerization of acrylic acid onto kappa-carrageenan in air

A novel biopolymer-based superabsorbent hydrogel was synthesized through chemically crosslinking graft copolymerization of acrylic acid (AA) onto kappa-carrageenan (κC), in the presence of a crosslinking agent and a free radical initiator. A proposed mechanism for κC-g-polyacrylic acid was suggested and the affecting variables onto graft polymerization (i.e. the crosslinker, the monomer and the initiator concentration, the neutralization percent and reaction temperature) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Maximum water absorbency of the optimized final product was found to be 789 g/g. The swelling capacity of the synthesized hydrogels was also measured in various salt solutions. The time-temperature profile of the polymerization reaction, in order to investigate the effect of molecular oxygen was conducted in terms of the absence and presence of the atmospheric oxygen. The overall activation energy (E_a) of the graft polymerization reaction was found to be 2.93 KJ/mol.