Surface modification of polyethylene terephthalate film by CO2 laser‐induced graft copolymerization of acrylamide

Graft copolymerization of acrylamide onto polyethylene terephthalate (PET) using a CO₂ pulsed laser was performed to improve water wettability. After laser irradiation in air, the films were placed in the aqueous solution of monomer and then heated to decompose peroxides formed onto the irradiated PET film. Peroxide density was determined spectrophotometrically by means of the iodide method. The grafted PET surfaces were characterized by attenuated total reflectance infrared spectroscopy, scanning electron microscopy, and contact angle measurements. The electron micrographs showed that the grafting changed the surface morphology of the PET film, which is consistent with the infrared spectra of the grafted films. To evaluate the surface hydrophilicity, water drop contact angle was determined. The contact angle decreased as a result of graft polymerization. It was also found that the hydrophilicity is related to the surface morphology and grafting level. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 401–407, 2000     

Structure and adhesion properties of linear low‐density polyethylene powders grafted with acrylic acid via ultraviolet light

The structure and adhesion properties of linear low‐density polyethylene (LLDPE) powder grafted with acrylic acid (AA) via ultraviolet light (UV) were studied by Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and water contact angle, peel strength, and graft degree measurements. The results show that the chemically inert LLDPE powder can be graft‐copolymerized with AA via this photografting method. The graft degree increases with the ultraviolet irradiation time. The hydrophilicity of the grafted LLDPE powder and the peel strength of high‐density polyethylene (HDPE)/steel joint with the grafted LLDPE powder used as hot‐melt adhesive are improved considerably, as compared to that with the ungrafted LLDPE powder. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2549–2553, 2006     

Characterization of acrylic acid‐grafted PP membranes prepared by plasma‐induced graft polymerization

Acrylic acid (AA)‐g‐polypropylene (PP) membranes were prepared by grafting AA on to a microporous PP membrane via plasma‐induced graft polymerization. The grafting of AA to the PP membrane was investigated using Fourier transform infrared spectroscopy (FTIR). Pore‐filling of the membranes was confirmed by field emission‐scanning electron microscopy (FESEM) and energy dispersing X‐ray (EDX). Ion exchange capacity (IEC), membrane electric resistance, transport number and water content were measured and analyzed as a function of grafting reaction time. The prepared AA‐g‐PP membranes showed moderate electrochemical properties as a cation‐exchange membrane. In particular, membranes with a degree of grafting of 155% showed good electrical properties, with an IEC of 2.77 mmol/g dry membrane, an electric resistance of 0.4 Ω cm² and a transport number of 0.96. Chronopotentiometric measurements indicated that AA‐g‐PP membranes, with a high IEC had a sufficient conducting region in the membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Plasma‐induced graft polymerization of acrylic acid onto poly(ethylene terephthalate) films

The graft polymerization of acrylic acid was carried out onto poly(ethylene terephthalate) films that had been pretreated with argon plasma and subsequently exposed to oxygen to create peroxides. The influence of synthesis conditions, such as plasma treatment time, plasma power, monomer concentration, temperature, and the presence of Mohr's salt, on the degree of grafting was investigated. The observed initial increase in grafting with monomer concentration accelerated at about 20% monomer. The grafting reached a maximum at 40% monomer and subsequently decreased with further increases in monomer concentration. The reaction temperature had a pronounced effect on the degree of grafting. The initial rate of grafting increased with increasing temperature, but the degree of grafting showed a maximum at 50°C. The activation energy of the grafting obtained from an Arrhenius plot was 29.1 kJ/mol. The addition of Mohr's salt to the reaction medium not only led to a homopolymer‐free grafting reaction but also diminished the degree of grafting. The degree of grafting increased with increasing plasma power and plasma treatment time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2993–3001, 2001     

Structure and adhesion properties of acrylic acid grafted high‐density polyethylene powders synthesized by a novel photografting method

A novel photografting, nonvapor, and nonliquid phase living graft polymerization was developed to functionalize high‐density polyethylene (HDPE) powder. The structure and adhesion properties of HDPE powder grafted with acrylic acid (AA) were studied by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), water contact angle, peel strength, and graft degree measurements. The result shows that HDPE powder can be grafted with AA via the method with a short reaction time and a high monomer conversion. The graft degree increases with the reaction time. Then, the hydrophilicity of the grafted HDPE powder increases also. The peel strength of HPDE/steel joint improved significantly when acrylic acid grafted HPDE powder was used as hot melt adhesive in place of ungrafted HDPE powder. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Characteristics of acrylic acid and N-isopropylacrylamide binary monomers–grafted polyethylene film synthesized by photografting

Method for introducing grafted chains consisting of two types of monomer components, acrylic acid (AA) and N-isopropylacrylamide (NIPAAm), into low-density polyethylene (PE) film (thickness = 25 μm) was investigated by two photografting technique using xanthone photoinitiator at 60°C. In the first method (one-step method), AA and NIPAAm binary monomers were graftcopolymerized onto PE film. In the second method (two-step method), AA was first photografted onto PE film and then NIPAAm was further introduced into the AA-grafted PE film by a second-step photografting. Water absorbencies of the grafted films (one- and two-step samples) prepared by the one- and two-step methods, respectively, decreased in the order of AA-grafted film > one-step sample > two-step sample > NIPAAm-grafted film. The water absorbency steeply decreased at 20 to 40°C with increasing temperature when immersed in water at the temperatures (5–60°C) for 24 h. Thermosensitivity, which was defined as the ratio of water absorbencies of the grafted samples at 5 and 60°C, was higher for the one-step sample than the two-step one. The different extent of the water absorbency and the thermosensitivity between both samples is discussed in terms of location of grafted chains in the film substrate, which was determined by electron probe microanalysis and attenuated total reflection–infrared measurements, and monomer sequence distribution of the grafted chains. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2057–2064, 1998     

Thermal crosslinking of collagen immobilized on poly(acrylic acid) grafted poly(ethylene terephthalate) films

Graft polymerization of acrylic acid onto plasma‐treated poly(ethylene terephthalate) (PET) films was used to prepare surfaces suitable for collagen immobilization by dip‐coating. Such surfaces could be used as matrices for smooth muscle cell cultures in tissue engineering. Contact angle measurements showed that plasma‐treated and grafted PET films undergo considerable surface reorganization during storage under ambient conditions. However, after collagen immobilization the contact angle remained relatively stable. The amount of collagen initially attached to the film surface increased with increasing poly(acrylic acid) graft density, but subsequent washing in water led to significant collagen loss. This loss could nevertheless be substantially reduced by thermal crosslinking of the collagen in the range 110–130 °C. Atomic force microscopy (AFM) observations suggested that the washed crosslinked collagen has a very similar structure to that of the un‐crosslinked collagen. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1874–1880, 2002     

Characterization of acrylic acid grafted poly(ethylene terephthalate) fabric

The preirradiation grafting of acrylic acid (AA) onto poly(ethylene terephthalate) (PET) had been found to affect the thermal and physical characteristics of fabric. The grafted fabrics with various graft levels were characterized by thermal gravimetric analysis (TGA), ATR‐FTIR spectroscopy, contact angle, differential scanning calorimetry (DSC), X‐ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The initial decomposition temperature and T₅₀ were increased with the increase in degree of grafting. The percentage crystallinity was decreased as the degree of grafting increases. The detailed elemental analysis was done by X‐ray photoelectron spectroscopy (XPS). The atomic ratio (O_1s/C_1s) was found to increase significantly with increasing the degree of grafting and reached 0.64 at 14.5% grafting from 0.38 for virgin PET. The surface topography and morphology was strongly influenced as the degree of grafting was increased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

超高相对分子质量聚乙烯接枝丙烯酸的制备

以丙烯酸为单体,采用γ射线辐照引发技术制备了超高相对分子质量聚乙烯接枝丙烯酸(UHMWPE- g-AA);利用傅里叶变换红外光谱和差示扫描量热法表征了接枝物的结构和热性能;用化学滴定法测定了接枝物的接枝率;研究了UHMWPE-g-AA对聚酰胺(PA)1010/UHMWPE-g-AA/UHMWPE共混物力学性能的影响。实验表明：接枝物在1716cm~(-1)处有明显的羰基特征吸收峰,说明AA分子确实被接枝到UHMWPE分子链上;接枝率随单体浓度、辐照剂量及辐照时间的增加而增加;加入UHMWPE-g-AA后,UHMWPE与PA1010的相容性得到了改善,PA1010/UHMWPE-g-AA/UHMWPE共混物的缺口冲击强度是PA1010/UHMWPE共混物的1.5倍,达到72J/m。     

Graft reaction of acrylic acid onto metallocene‐based polyethylene‐octene elastomer

In this study, grafting of acrylic acid (AA) onto metallocene‐based polyethylene‐octene elastomer (POE) was investigated by using benzoyl peroxide as an initiator. Grafted product was characterized by using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X‐ray diffraction spectroscopy, and differential scanning calorimetry (DSC). Both the grafting percentage and the gel yield, at equilibrium, were higher for POE containing lower degree of comonomer content. In all cases, the crosslinking reaction was accompanied by the predominant graft reaction due to the competition of POE macroradical and excited AA. From the result of DSC and X‐ray characterizations, it was found that the change of crystallinity is slight when the gel is removed from POE‐g‐AA copolymers. It was also proven that the effect of gel formation on the properties of the copolymer could be neglected because of the low gel yield. So, the graft method proposed in this article can produce low gel yield copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2905–2912, 2002     

On promoting intercalation and exfoliation of bentonite in high‐density polyethylene by grafting acrylic acid

Acrylic acid (AA) grafted high‐density polyethylene (HDPE)/bentonite (BT) composites and HDPE/BT composites were prepared via melt compounding. XRD and TEM results indicated that the modification of AA grafting promoted the dispersion and intercalation of BT in HDPE matrix; IR proved that there were interactions between AA and BT sheets. Consequently, with increasing BT content, the tensile strength and Young's modulus of HDPE‐g‐AA/BT nanocomposites increased, while that of HDPE/BT composites decreased. Moreover, the addition of BT to HDPE‐g‐AA decreased the ability of crystallization of the matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2429–2434, 2005     

Performance evaluation of synthesized acrylic acid grafted polyethylene in aluminum hydroxide highly filled polyethylene composites

A polymeric agent acrylic acid grafted polyethylene (AAgPE) was synthesized and used as a coupling agent in aluminum hydroxide [Al(OH)₃] highly filled linear low‐density polyethylene (LLDPE) composite. It is found that AAgPE improves the interfacial adhesion between the filler and the polyethylene matrix, which results in good mechanical properties of the composite. Silicon oil is an effective additive for improving the impact strength, the elongation at break, and the rheological property of the filled composite, but it decreases the tensile strength remarkably. The combination of AAgPE and silicon oil can lead to good performance of the composite. Flammability properties and fracture surface morphologies of the composites through scanning electron microscopy were investigated. The relationship between mechanical properties and microstructure of the composites was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2544–2549, 2002     

用低温等离子体诱导PET织物接枝丙烯酸

运用氧气等离子体表面改性技术对PET织物进行处理后接枝丙烯酸,探讨了处理时放电功率、单体浓度、反应温度、处理时间等对接枝率的影响,并对接枝率与织物的吸湿性进行了研究。     

Adhesion of surface‐grafted low‐density polyethylene plates with enzymatically modified chitosan solutions

An investigation was undertaken on application of dilute chitosan solutions modified by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenetylamine (dopamine) to adhesion of the low‐density polyethylene (LDPE) plates surface‐grafted with hydrophilic monomers. Tensile shear adhesive strength effectively increased with an increase in the grafted amount for methacrylic acid‐grafted and acrylic acid‐grafted LDPE (LDPE‐g‐PMAA and LDPE‐g‐PAA) plates. In particular, substrate breaking was observed at higher grafted amounts for LDPE‐g‐PAA plates. The increase in the amino group concentration of the chitosan solutions and molecular mass of the chitosan samples led to the increase in adhesive strength. Adhesive strength of the PE‐g‐PMAA plates prepared at lower monomer concentrations sharply increased at lower grafted amounts, which indicates that the formation of shorter grafted PMAA chains is an effective procedure to increase adhesive strength at lower grafted amounts. Infrared measurements showed that the reaction of quinone derivatives enzymatically generated from dopamine with carboxyl groups was an important factor to increase adhesive strength in addition to the formation of the grafted layers with a high water absorptivity. The above‐mentioned results suggested that enzymatically modified dilute chitosan solutions can be applied to an adhesive to bond polymer substrates. The emphasis is on the fact that water is used as a solvent for preparation of chitosan solutions and photografting without any organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on acrylic acid–grafted polyester fabrics by electron beam preirradiation method. I. Effects of process parameters on graft ratio and characterization of grafting products

Polyester fabrics were preirradiated by electron beam in air and then grafted by acrylic acid (AA) without excluding oxygen. Effects of preirradiation dose, monomer concentration, reaction temperature, storage time, sulfuric acid, and Mohr's salt were investigated in detail and are discussed. The results suggest that it is practicable and effective to graft AA onto polyester fabrics by means of the preirradiation method. FTIR and SEM were used to characterize AA‐grafted polyester fabrics. A new band appearing at 1546 cm^?1 in the FTIR spectrum implies that AA was indeed introduced onto PET macromolecules. Changes of the diameter and the surface structure of fabric fibers presented in SEM micrographs make it clear that a layer of grafted poly(acrylic acid) was formed on the surface of these PET fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3931–3938, 2003     

丙烯酸与异形聚酯共混纤维接枝共聚研究

以过氧化苯甲酰为引发剂,丙烯酸为单体与碱处理后的异形聚酯共混纤维接枝共聚,井对接枝后的异形聚酯共混纤维进行了结构和性能研究。结果表明:BPO浓度在0．01 moL／L,丙烯酸浓度1．50 mol/L,聚合温度85℃,时间90 min,所获得的接枝率为12％。随着接枝率的上升,热稳定性下降,回潮率增加,抗静电性能增加。     

Improvement in adhesive‐free adhesion by the use of electrostatic interactions between polymer chains grafted onto polyethylene plates

The tensile shear adhesive‐free adhesion properties induced by electrostatic interactions between poly(acrylic acid) (PAA) and poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) chains grafted onto polyethylene (PE) with low‐density (LDPE) or high‐density (HDPE) plates were studied. PAA‐ or PDMAEMA‐grafted PE plates were immersed in a HCl or NaOH solution or water for 24 h, and their electrostatic properties were changed before they were overlapped with each other and heat‐pressed. The breaking of the substrate between the two plates with water‐swollen grafted layers was observed in the low range of grafted amounts in comparison with immersion in the acidic and basic solutions. The ability of the two plates with grafted polymer chains swollen in water to strongly bond with each other was a result of electrostatic interactions formed by positively charged PDMAEMA and negatively charged PAA chains. The breaking of the substrate in the case of adhesive‐free adhesion between quaternized PDMAEMA‐grafted and PAA‐grafted PE plates immersed in the basic solution occurred with lower grafted amounts of PAA. This came from the strong attractive force between dissociated anionic PAA chains and quaternized cationic PDMAEMA chains in the basic solution. In addition, the adhesive‐free adhesion strength of HDPE plates with the same grafted polymer chains encountered the breaking of the substrate with lower grafted amounts than that of LDPE plates. It was concluded that the grafting of polymer chains onto HDPE plates with high crystallinity was considerably restricted to the outer surface regions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2632–2638, 2006     

丙烯酸接枝改性PET纤维的结构与性能

采用丙烯酸接枝改性聚对苯二甲酸乙二酯(PET)纤维,探讨了接枝率对PET纤维结构、回潮率、染色性能以及力学性能的影响。结果表明:随着接枝率的增加,PET纤维密度变化不大,双折射率略为下降,纤维的吸湿性、抗静电性和染色性能提高,拉伸性能有所下降。当接枝率为10.78%时,PET纤维经0.03 mol/L的Na_2CO_3溶液处理后,其质量比电阻为1.34×10~6Ω·g/cm~2,回潮率为5.05%,纤维拉伸强度为3.31 cN/dtex,上染率达93.8%。     

环保型木薯淀粉接枝丙烯酸共聚物的合成研究

以N,N'-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用水溶液聚合法制备了木薯淀粉接枝丙烯酸高吸水性树脂.考察了淀粉含量、中和度、引发剂用量、交联剂用量等因素对反应的影响.结果表明:在木薯淀粉含量为10%,引发剂用量为0.3%,交联剂用量为0.025%,丙烯酸与氢氧化钠的中和度为85%的条件下,制备得到的吸水性树脂吸水率达1355 g·g-1,其吸水速率快、加压保水能力强、热稳定性好.     

Lamination of high‐density polyethylene by bulk photografting and the mechanism of adhesion

The photolamination of high‐density polyethylene (HDPE) by bulk photografting is described, along with a discussion of the adhesion mechanism. HDPE can be photolaminated very easily with a thin poly(acrylic acid) layer, photopolymerized from acrylic acid, with very strong adhesion obtained after a short time of UV irradiation; the adhesion failure mode is polyethylene breakage. Thicker HDPE sheets require longer irradiation times for strong adhesion. Methacrylic acid or hydroxyethyl methacrylate provides no adhesion of HDPE at all after irradiation. When glycidyl acrylate is used alone between HDPE sheets, the peel strength of the photolaminated polyethylene is only approximately 320 N/m, but when glycidyl acrylate or hydroxyethyl methacrylate is grafted with acrylic acid, very good adhesion can be obtained. It is proposed that stronger adhesion is produced by a less branched grafted chain structure, which permits much more chain entanglement. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1097–1106, 2005