Properties Of Graft Copolymers Research Articles

Polar poly(n-butyl acrylate)-g-polyacrylonitrile elastomer with high temperature elasticity and healability as flexible electronic substrate

In this work, graft copolymer poly (n-butyl acrylate)-g-polyacrylonitrile with poly (n-butyl acrylate) as backbones and polyacrylonitrile as side chains (PnBA-g-PAN) was synthesized by macromonomer method and emulsion polymerization. The macromonomer was synthesized by atom transfer radical polymerization and end-group modification. The chemical structures and thermal properties of macromonomer and graft copolymer were investigated by FTIR, GPC, NMR and TGA, etc. The mechanical properties of graft copolymer elastomer was also measured by uniaxial tensile test. Rheological properties at different temperature and mechanical property demonstrated that graft copolymer elastomer possessed elasticity until 180 oC because of cyclization of cyano groups. Ag nanowires@PnBA-g-PAN composite elastomer was developed, and the resulted material exhibited autonomic healing property on account of segments’ flexibility and dynamic interaction between Ag nanowires (AgNWs) and cyano groups. This is a general method for generation of elastomer with high temperature elasticity and fast self-healing. The composite elastomer has potential application in flexible electronic conductor.

Synthetized Potato Starch-A New Eco Sizing Agent for Cotton Yarns.

The objective of this research was to verify the feasibility of the use of newly synthesized biopolymer materials for sizing cotton yarns based on the basic principles of chemical modification. Research included acid hydrolysis of potato starch up to controlled molar masses together with graft-polymerization and methacrylic acid onto hydrolyzed starch to improve hydrophilicity and solubility, to increase the capability of film forming, to increase adhesive potential and to avoid retrogradation phenomena. Research objectives were primarily focused on finding an appropriate, environmentally-friendly and productive sizing agent for cotton yarns via the analysis and systematization of a large number of synthesis methods in conjunction with the characterization and properties of graft-copolymers. The research results showed that potassium persulfate initiator was most efficient in grafting of methacrylic acid onto hydrolyzed starch, while azobisisobutyronitrile (AIBIN) initiator was most efficient in grafting of acrylic acid (AC). FTIR analysis confirmed that new and efficient products for sizing cotton yarns from synthetized potato starch were obtained. Research on rheological properties of copolymers shows a higher viscosity of grafted products indicating the good stability of potential starches. Ecological improvements have been established through high desizing degree as well as improvements in physical-mechanical properties of yarn, abrasion resistance and decrease in yarn surface hairiness were noticed. The use of new derivatives of potato starch, especially of hydrolyzed starch grafted with methacrylic acid (MAA), potassium persulfate (KPS) as initiator, was confirmed. Anova statistical analysis determined the influence of the entire sizing process on individual yarn parameters.

Allyl-Terminated Polypropylene Macromonomers: A Route to Polyolefin Elastomers with Excellent Elastic Behavior

We report the design, synthesis, and physical/mechanical properties of graft copolymers containing semicrystalline polypropylene side chains and amorphous ethylene/α-olefin copolymer backbones. These materials, a new class of semicrystalline, polyolefin-based thermoplastic elastomers, are made in two steps. First, allyl-terminated syndiotactic or isotactic polypropylene macromonomers are synthesized with controlled microstructure and molecular weight using bis(phenoxyimine)titanium or chiral ansa-zirconocene catalysts, respectively. Second, a pyridyl-amido hafnium catalyst is used to copolymerize the macromonomer, ethylene, and an α-olefin with precise control of composition and side chain incorporation. With highly crystalline polypropylene side chains and amorphous backbones of low glass-transition temperatures (<−55 °C), the samples have strain-to-break values up to 1400% and elastic recovery above 85% at maximum strains up to 1000%. The synthetic method described herein does not require the use of a l...

Effect of Structure of Graft on the Properties of Graft Copolymers of Acrylamide and Surfactant Macromonomers Dilute Aqueous Solutions

Several surfactant macromonomers (SMMxyz) were prepared by using triblock polymers of ethylene oxide (EO) and propylene oxide (PO) (POx–EOy–POz triblock polymer, x: y: z represent the weight ratio of the different blocks). Then graft copolymers of acrylamide and SMMxyz (PAM-g-SMMxyz) were synthesized. The effects of EO/PO mole ratio, length of grafted SMMxyz and the three relative block sizes on the surface activity and thermo-associativity of PAM-g-SMMxyz dilute solutions were studied. The results showed that the surface tension decreased with increasing PO in the graft at 30°C and decreased with the length of the graft when the temperature was higher than the cloud points of the grafted POx–EOy–POz chains, regardless of EO/PO ratio. When the EO/PO ratio was the same in the SMMxyz, the PAM-g-SMMxyz with higher PO content at the graft end had higher surface activity. With increasing temperature, the hydrodynamic radius (Rh) of PAM-g-SMMxyz in dilute aqueous solution increased. The polymer with shorter grafts may have much more intermolecular interaction points and there were more polymer chains in the polymeric aggregates, which led to Rh increasing with decreasing length of graft. In addition, when the EO/PO was not more than 1:1.74, the three relative block sizes had no great influence on the temperature-associativity of PAM-g-SMMxyz. However, for PAM-g-SMM217 and PAM-g-SMM712, the Rh of PAM-g-SMM217 was smaller than PAM-g- SMM712.

Preparation and characterisation of amphiphilic chitosan

The amphiphilic graft copolymer using chitosan and hydroxypropyl chitosan (HPCS) as hydrophilic backbone and poly(l-lactide) (PLLA) as the hydrophobic segment was prepared by a two-step method. Hydroxypropyl chitosan was prepared first by the reaction of chitosan and propylene oxide in isopropanol, then the HPCS graft copolymerisation was carried out by ring opening polymerisation of lactide with Ti(OBu)4 as catalyst in dimethyl sulphoxide (DMSO) under a nitrogen atmosphere, and finally HPCS-graft-PLLA (HPCS-g-PLLA) copolymers were obtained. Chitosan-graft-PLLA copolymers were prepared using the same conditions. The physical and chemical properties of graft copolymers were characterised using Fourier transform infrared, 1H–nuclear magnetic resonance, X-ray diffraction and thermogravimetric analysis. Solubility tests showed that HPCS-g-PLLA have good solubility in deionised water and DMSO.

Optimization grafting conditions and characterization of methyl cellulose grafted polyacrylonitrile copolymer

Methyl cellulose-graft-polyacrylonitrile (MC-g-PAN) copolymer was synthesized by free-radical polymerization using cerium ammonium nitrate (CAN) as an initiator in an aqueous medium. The characteristics were found to depend primarily on the polyacrylonitrile content rather than the graft density or the polyacrylonitrile chain length according to reaction parameters, such as CAN concentration, acrylonitrile concentration, reaction temperature, and reaction time. The successful grafting was confirmed using various analytical tools including FTIR, 1H NMR, XPS, XRD, and TGA. The percentage of graft copolymerization increased with increasing monomer and CAN concentration. The mechanical properties of graft copolymers were measured and investigated as a function of the ratio of grafting.

Effect of various initiators on molar mass determination of hydrolyzed potato starch-acrylamide graft copolymers

This study is concerned with synthesis, characterization and properties of graft copolymer produced from hydrolyzed potato starch and acrylamide using various initiators (azobisisobutyronitrile, potassium persulfate and benzoyl peroxide). Starch hydrolysis was performed in order to reduce molecular mass. Acrylamide was grafted on shorter starch macromolecules creating side branches on the main chain resulting in a product that could be used in textile finishing more successfully. Various initiators were used, primarily, to produce graft monomer on the starch and also to obtain thinner or thicker packaging of side chains that can have a great influence on the behavior of textile yarns impregnated with these copolymers. Benzoyl peroxide, as initiator, proved to be very successful in grafting of acrylamide on hydrolyzed starch, in terms of yield, graft percentage and efficiency results. Grafting in the presence of azobisisobutyronitrile and potassium persulfate as initiators has slightly better monomer to polymer conversion values. FTIR spectra of hydrolyzed and grafted starch confirm by their characteristic bands that grafting was successful. Residual amounts of monomer in copolymer and molar mass distribution were determined by chromatography. Results show that the highest quantity of monomer is found in the sample of hydrolyzed starch grafted in the presence of potassium persulfate. Molar masses of hydrolysate and copolymer show differences ranging from 1?102 to 2?107 g/mol. Results of sizing using grafted starch show that sized yarns had higher strength (tenacity) and lower elongation. Grafted hydrolyzed starch, as an agent for cotton yarn sizing, gives better results than non grafted starch, especially regarding sizing uniformity, yarn mechanical parameters and easier removal in following desizing process.

Study on Synthesis and Properties of a Starch-Polyacrylamide Graft Copolymer by HRP

A starch-polyacrylamide graft copolymer has been synthesized in water by means of horseradish peroxidase (HRP)/H2O2/acetylacetone (ACAC). It is discussed through single factor experiment that the effects of system pH, reaction temperature and amount of HRP on the residual acrylamide (AAM) content. The results show that the ideal copolymer was synthesized when mass ratio of starch and AAM was 2:1, and catalyst was HRP/H2O2 at 30 °C for 3.5 h. The residual AAM content was about 1.0%. The structure and properties of the graft copolymer are characterized by FTIR, NMR. The graft copolymer is used as retannage.

Study on Synthesis and Properties of a Starch-Polyacrylamide Graft Copolymer by HRP

A starch-polyacrylamide graft copolymer has been synthesized in water by means of horseradish peroxidase (HRP)/H2O2/acetylacetone (ACAC). It is discussed through single factor experiment that the effects of system pH, reaction temperature and amount of HRP on the residual acrylamide (AAM) content. The results show that the ideal copolymer was synthesized when mass ratio of starch and AAM was 2:1, and catalyst was HRP/H2O2 at 30 °C for 3.5 h. The residual AAM content was about 1.0%. The structure and properties of the graft copolymer are characterized by FTIR, NMR. The graft copolymer is used as retannage.

Grafting of 4‐Vinyl Pyridine onto Nylon‐6 Initiated by Redox System

AbstractThe graft copolymerization of 4‐vinyl pyridine (4VP) onto nylon‐6 (PA6) was studied by using potassium diperiodatonickelate(IV) (DPN)‐PA6 redox system in alkaline medium. The structures of graft copolymers were confirmed by Fourier transfer infrared spectroscopy (FTIR) and X‐ray diffraction. The properties of graft copolymers were investigated by thermogravimetric analysis (TGA). A mechanism was proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of 4VP to PA6, pH as well as reaction temperature and time were investigated. Graft copolymers with high grafting efficiency (&gt;95%) were obtained, which indicated that DPN‐PA6 redox system is an efficient initiator for this graft copolymerization. The quaternized PA6‐g‐P4VP (QPAVP) was proved to be an excellent adsorbent to heavy metal ions.

Preparation and Properties of Graft Copolymer of Phenols and Starch with HRP Catalysis

A graft copolymer was synthesized by means of radical copolymerization of degraded starch, phloroglucinol(PG) and sulfanilic acid (SA) and the reaction was catalyzed by horseradishperoxidase (HRP)/H2O2. It was discussed that the effectsof monomer composition, the temperature and system pH on the graft copolymerization. The ideal copolymer was synthesized in the pH 7.0 at 30°C when the molar ratio of PG and SA was 5:6. The structure of the copolymer was characterized by Fourier Transform Infrared (FTIR) spectroscopy. Meanwhile, the graft copolymer has been used in tanning process. The retanned leather exhibits excellent increase ratio in leather thickness and good dyeing ability which indicate that the graft copolymer has retanning and assisting dyeing properties.

Well-defined graft copolymers: from controlled synthesis to multipurpose applications

Graft copolymers with a large number of side chains chemically attached onto a linear backbone are endowed with unusual properties thanks to their confined and compact structures, including wormlike conformation, compact molecular dimensions and notable chain end effects. Growing attention has been paid to these interesting macromolecules due to their importance in understanding the correlation between architectures and properties, as well as their potential applications. To date, the synthesis and properties of graft copolymers in both solution and bulk have been extensively investigated, along with their applications. In this tutorial review, recent advances in synthetic approaches towards the construction of well-defined graft copolymers are discussed in detail and applications of these interesting macromolecules are highlighted by selected examples.

Study on Preparation and Properties of Starch and 4-Phenolsuflonate Graft Copolymer with HRP Catalysis

Degraded starch was reacted with 4-phenolsuflonate (PHS) in water in the presence of horseradish peroxidase (HRP) catalyst/H2O2/acetylacetone (ACAC) to give starch and PHS graft copolymers. The structure and properties of the graft copolymer are characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR). The retanned leather exhibits excellent increased thickness and softness, good dyeing ability and eligible mechanical properties.

Grafting of 4‐Vinyl Pyridine onto Nylon‐6 Initiated by Cu(III)

In this article, the graft copolymerization of 4‐vinyl pyridine (4VP) onto nylon‐6 (PA6) using potassium diperiodacuprate (III) (DPC)–PA6 redox system as initiator is investigated in an alkaline medium. The structure and the properties of graft copolymer are confirmed by Fourier transfer infrared spectroscopy (IR), X‐ray diffraction and thermogravimetric analysis (TGA). The mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, ratio of 4VP to PA6, pH, as well as reaction temperature and time are investigated. Graft copolymers with high grafting efficiency (>95%) were obtained, which indicated that the DPC–PA6 redox system was an efficient initiator for this graft copolymerization. The quaternized PA6‐g‐P4VP (QPAVP) is proven to be an excellent adsorbent to heavy metal ions.

Synthesis and Characterization of a Novel Conducting Graft Copolymer

The electrically conductive graft (g) copolymer, poly(dimethylolpropionic acid –co-adipoyl chloride)-g-poly(aniline) (PDMPAAC-g-PAni) was prepared by the electrochemical polymerization of aniline (Ani) using a precursor polymer, poly[(4-aminophenyl)-dimethylolpropionic amide-co-adipoyl chloride] (PADMPAAC). PADMPAAC was synthesized chemically by reacting PDMPAAC with 1,4-phenylenediamine. The electrochemical properties of graft copolymer are compared with those of PDMPAAC/PAni composites. Synthesis of PDMPAAC and PADMPAAC was characterized using 1H-NMR, FT-IR spectroscopy. The electrochemical properties of the novel conducting copolymer were investigated using cyclic voltammetry (CV) and chronoamperometry (CA); thermal properties were investigated using thermogravimetric analysis (TGA). The electric conductivity was measured with four-probe method.

Graft Copolymers with Chemically Complementary Components as a Special Class of High‐Molecular‐Weight Compounds

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and properties of graft copolymer derived from polyurethane and dihydroxyacrylate of bisphenol A

In this investigation, polyurethane was grafted with dihydroxyacrylate of bisphenol A, in basic medium, at 80°C. The grafting process was studied using an acrylate–urethane model compound. The grafting degree of polyurethane with dihydroxyacrylate of bisphenol A was 9% by weight. An alkylation mechanism of the synthesis of the graft copolymer was suggested. The addition of the acrylic double bond to the NH–urethane structures takes place in the first stage, and the reaction can be continued as a transposition in the ortho position of the aromatic ring in the second stage. The synthesized graft copolymer was crosslinked at 140°C in the presence of pyridine. The crosslinked copolymer shows high mechanical properties as compared to polyurethane, as well as an improvement of polyurethane's thermal stability. The solubility parameter of the synthesized crosslinked copolymer was estimated to have a value of 11.57 (cal/mol)1/2. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1802–1813, 2001

Structure and properties of graft copolymers of polyethylene terephthalate with polytetrafluoroethylene

-- Using IR-spectroscopy, x-ray diffraction, and electron microscopy, we have investigated the change in supermolecular structure of graft copolymers of PET with PTFE.

Synthesis and Some Properties of Graft Copolymers with Uniform Polyoxyethylene Side Chains

Abstract Graft copolymers with uniform polyoxyethylene (PEO) side chains were synthesized by transesterification of poly(methyl, ferf-butyl fumarate) (PMtBF) or poly(methyl, tert-butyl fumarate-co-styrene) poly-(MtBF-co-St) with potassium alkoxide of PEO monoether. The grafting efficiency increased with enhanced alkoxide reactivity, but the main factor in the ester exchange proved to be the structure of the backbone. This effect was ascribed to the thermodynamic incompatibility between fumaric polymers and PEO. The polymers were characterized by spectral methods, GPC, and DSC. In THF the graft copolymers comprising a polyfumarate backbone with PEO side chains eluted at higher elution volumes than did the backbone homopolymers. In benzene their intrinsic viscosities were lower than those of the backbones. In aqueous eluents, micelles were detected, and their aggregation number depended on the composition of the copolymer and the eluent.

Water Sorption by Graft Copolymers of Polyamide and Poly-N,N-Dimethylaminoethyl Methacrylate

Abstract This paper deals with the investigation of sorption and structural properties of graft copolymers of polycaproamide and poly-N,N-dimethylaminoethyl methacrylate. It is shown that the portion of hydrolyzing amide groups does not exchange after grafting. All samples have equal solubility, but diffusion coefficients depend on grafting degrees, and the zero coefficient is a function of CONH-group concentration.