Characterization Of Graft Copolymers Research Articles

Synthesis and Characterization of Graft Copolymers with Poly(ε-caprolactone) Side Chain Using Hydroxylated Poly(β-myrcene-co-α-methyl styrene).

Graft copolymers have unique application scenarios in the field of high-performance thermoplastic elastomers, resins and rubbers. β-myrcene (My) is a biomass monomer derived from renewable plant resources, and its homopolymer has a low glass transition temperature and high elasticity. In this work, a series of tapered copolymers P(My-co-AMS)k (k = 1, 2, 3) were first synthesized in cyclohexane by one-pot anionic polymerization of My and α-methyl styrene (AMS) using sec-BuLi as the initiator. PAMS chain would fracture when heated at high temperature and could endow the copolymer with thermal degradation property. The effect of the incorporation of AMS unit on the thermal stability and glass transition temperature of polymyrcene main chain was studied. Subsequently, the double bonds in the linear copolymers were partially epoxidized and hydroxylated into hydroxyl groups to obtain hydroxylated copolymer, which was finally used to initiate the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) to synthesize the graft copolymer with PCL as the side chain. All these copolymers before and after modifications were characterized by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), thermogravimetry analysis (TGA), and differential scanning calorimeter (DSC).

Synthesis and Characterization of Graft Copolymers Containing Polymeric Linoleic Acid by Atom Transfer Radical Polymerization and Condensation Reaction

Bu çalışmada, NPLina1-g-PCL-g-PSt üç bloklu graft kopolimerler Atom Transfer Radikal Polimerizasyonu (ATRP) ve kondenzasyon reaksiyonu kullanılarak bir basamakta tek kap (one-pot) yöntemiyle sentezlendi. Polimerik linoleik asit dietanolaminle reaksiyona sokularak hidroksillenmiş linoleik asit polimerleri (NPLina1, NPLina2 ve NPLina3) elde edilmiştir. ε-Kaprolakton'nun (ε-CL) kalay (II) 2-etilheksanoat katalizörü varlığında 110 °C'de halka açılma polimerizasyonuyla poli(ε-kaprolakton) (PCL) sentezlenip, ardından 2-bromopropiyonil bromür ile esterleşmesi sonucu bromlanmış poli(ε-kaprolakton) (PCL-Br) makro başlatıcısı hazırlandı. Tek kap yöntemiyle, stiren (St) monomerinin PCL-Br makro başlatıcısıyla CuCl/PMDETA sistemi varlığında [I]:[CuCl]:[PMDETA] = 1:1:3 mol oranları kullanılarak, 110 °C’de toluen içinde ATRP'si ile NPLina1’nın kondenzasyon reaksiyonu aynı anda gerçekleştirildi. Böylece, kontrollü molekül ağırlıklarına ve orta derecede dar polidispersitelere sahip graft kopolimerler elde edildi. Tek basamakta gerçekleşen polimerizasyon üzerine monomer konsantrasyonu, başlatıcı konsantrasyonu ve polimerizasyon süresi gibi temel parametreler incelendi. Elde edilen polimerler, proton nükleer manyetik rezonans (1H NMR), fourier dönüşümlü kızılötesi spektroskopisi (FTIR) ve jel geçirgenlik kromatografısi (GPC) teknikleri kullanılarak karakterize edildi.

Design, fabrication, and characterization of graft co-polymer assisted ocular insert: a state of art in reducing post-operative pain

Purpose Targeted delivery of drugs at appropriate concentrations to ocular tissues is required to avoid wastage. Hence, advanced systems that maximize the release of poorly soluble drugs and deliver them at ocular sites must be designed. Methods In this study, Soluplus® (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol–graft copolymer) was selected as a solubilizer as well as film former for preparing ocular inserts and polyethylene glycol 400 (PEG-400) as a plasticizer. On the basis of an initial phase solubility study, the maximum concentration of Soluplus® possible was used for developing the inserts. An optimized formulation was obtained using a 32-factorial design. Two factors at three levels were used to design the ocular inserts. Soluplus® (X 1) and the plasticizer, PEG-400 (X 2), were set as the independent variables at various levels, and the Rel4h (drug release in 4 h, Y 1) and tensile strength (Y 2) were set as the dependent variables. A pre-formulation study was conducted to select suitable materials. Results Various physico-chemical parameters of the optimized formulation, including the tensile strength and folding endurance, were studied using FT-IR, DSC, XRD, and SEM. An in vitro dissolution study was conducted to determine the amount of drug released. There was no redness, swelling, or watering of the rabbit eye. Conclusion It was concluded that the ocular inserts of the poorly soluble nepafenac developed using a graft-co-polymer enhanced the solubility and utilization of the drug for a prolonged period.

Cooperative Folding of Linear Poly(dimethyl siloxane)s via Supramolecular Interactions.

The synthesis and characterization of graft copolymers are reported based on linear poly(dimethyl siloxane) (PDMS) and chiral, pendant benzene-1,3,5-tricarboxamides (BTAs). The copolymers differ in degree of polymerization (DP) and BTA graft density. Characterization of the bulk materials at room temperature reveals that the BTAs aggregate in a helical fashion via threefold hydrogen-bond formation within the PDMS matrix. A significant degree of hydrogen bonding persists up to 180 °C, regardless of DP and BTA content. Analysis of the solution behavior by 1 H NMR spectroscopy indicates that BTA aggregation occurs in CDCl3 , a solvent normally suppressing aggregation. Circular dichroism (CD) spectroscopy in 1,2-dichloroethane shows strong CD effects and reveals that increasing the DP and decreasing the BTA graft density results in an increase in the cooperativity of the BTA aggregation. Dynamic light scattering indicates the formation of particles with sizes of 400 nm. This is the first time that polymers with pendant BTAs show a sharp transition between a nonaggregated and aggregated state, a behavior similar to the one observed for "free" BTAs. The cooperative aggregation is attributed to the strong phase-segregation between the PDMS backbone and the BTAs, in combination with a high propensity of these polymers to form multichain aggregates.

The Synthesis and Structural Characterization of Graft Copolymers Composed of \u03b3-PGA Backbone and Oligoesters Pendant Chains

The novel copolymers composed of poly-γ-glutamic acid (γ-PGA) and oligoesters have been developed. The structures of the obtained copolymers including variety of end groups were determined at the molecular level with the aid of electrospray ionization multistage mass spectrometry (ESI-MSn). The fragmentation experiment performed for the selected sodium adducts of the copolymers confirmed that the developed methods lead to the formation of graft copolymers composed of poly-γ-glutamic acid (γ-PGA) backbone and oligoesters pendant chains. Moreover, it was established that fragmentation of selected sodium adducts of graft copolymers proceeded via random breakage of amide bonds along the backbone and ester bonds of the oligoesters pendant chains. Considering potential applications of the synthesized copolymers in the area of biomaterials, the hydrolytic degradation under laboratory conditions and in vitro cytotoxicity tests were performed. The ESI-MSn technique applied in this study has been proven to be a useful tool in structural studies of novel graft copolymers as well as their degradation products.Graphical ᅟ

Synthesis and characterization of graft copolymers based on polyepichlorohydrin via reversible addition-fragmentation chain transfer polymerization

ABSTRACTIn this study, synthesis of poly(epichlorohydrin-g-methyl methacrylate) graft copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization was reported. For this purpose, epichlorohydrin was polymerized by using HNO3 via cationic ring-opening mechanism. A RAFT macroinitiator (macro-RAFT agent) was obtained by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin. The graft copolymers were synthesized using macro-RAFT agent as initiator and methyl methacrylate as monomer. The synthesis of graft copolymers was conducted by changing the time of polymerization and the amount of monomer-initiator concentration that affect the RAFT polymerization. The effects of these parameters on polymerization were evaluated via various analyses. The characterization of the products was determined using 1H-nuclear magnetic resonance (1H-NMR), Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, elemental analysis, and fractional precipitation techniques. The block lengths of the graft copolymers were calculated by using 1H-NMR spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations.

Electron beam radiation grafting of styrene on natural rubber using Taguchi's design

Graft copolymer of natural rubber (NR) and polystyrene was successfully prepared by electron beam irradiation for the first time. The experiments were designed based upon the Taguchi method, using Minitab software, in order to reduce the number of experiments. The radiation dose was varied from 25 to 100 kGy. The content of sensitizer (n-BA) was varied from 0 to 5 phr. Various NR/St ratios were used: 90:10, 80:20, 70:30, and 60:40. Characterization of graft copolymer was confirmed by Fourier transform infrared spectroscopy (FTIR)and transmission electron microscopy (TEM) techniques. The core–shell structure of graft copolymer was obtained and the monomer conversion, grafting efficiency, grafting yield, and crosslink density were studied. Optimum conditions were determined by the experimental design: radiation dose of 75 kGy, content of n-BA of 5 phr, and NR/St ratio of 80:20. Finally, the tensile strength of latex films was found to be significantly related to the studied factors.

Synthesis and characterization of graft copolymers by photoinduced CuAAC click chemistry

Well-defined graft copolymers were synthesized by a simple photoinduced copper(I) catalyzed 1,3-dipolar cycloaddition click reaction of alkyne-terminated poly(epsilon-caprolactone) (PCL) either side-chain azide-functional polystyrene (PSt) or poly(vinyl chloride) (PVC). The alkyne-terminated PCL was prepared by ring-opening polymerization of epsilon-caprolactone in bulk using Sn(Oct)2 as a catalyst and propargyl alcohol as an initiator. Whereas, the halide groups of PVC and poly(styrene-co-chloromethylstyrene) prepared by nitroxide mediated radical copolymerization were transformed to side chain azide-functional PVC or PSt via nucleophilic substitution reaction using sodium azide. Subsequently, the resulting alkyne and azide functional polymers were mixed in DMF with Cu(II)Br2/PMDETA ligand and 2, 2-dimethoxy-2-phenyl acetophenone and irradiated by UV light to form corresponding graft copolymers. The FT-IR, 1H NMR, GPC and DSC analyzes clearly pointed out an efficient photoinduced CuAAC click reactions between azide- and alkyne-functional precursor polymers.

Preparation and characterization of graft copolymer from dealkaline lignin and styrene

ABSTRACTGraft copolymerization of styrene onto dealkaline lignin by ferrous chloride and hydrogen peroxide coinitiator has been achieved successfully. The influence of temperature and reaction time as well as the amount of the styrene monomer, initiator, and catalyst on the grafting copolymerization was investigated. The optimum reaction conditions were determined as follows: c (styrene) = 20.00 mmol, c (H2O2) = 5.00 mmol, c (FeCl2) = 0.10 mmol, T = 30°C and t = 48 h. The optimum yield (Y), total conversion (TC), grafting efficiency (GE), and degree grafted (DG) values were 96.6, 96.3, 59.5, and 53.7%, respectively. The copolymer of lignin grafted PS was separated and characterized by elemental analysis, differential scanning calorimetry, Fourier transform infrared, thermogravimetry analysis, field emission‐scanning electron microscopy, gel permeation chromatography, and nuclear magnetic resonance. It was demonstrated that the solubility what the copolymer exhibited turned out to be the very reverse of the original lignin. The surface properties and structure of lignin were completely changed after grafting copolymerization. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41900.

Correction: Synthesis and characterization of graft copolymers PnBA-g-PS by miniemulsion polymerization

Correction for ‘Synthesis and characterization of graft copolymers PnBA-g-PS by miniemulsion polymerization’ by Hui Li et al., RSC Adv., 2015, 5, 45459–45466.

Synthesis and characterization of graft copolymers PnBA-g-PS by miniemulsion polymerization

PnBA-g-PS by emulsion AGET ATRP and miniemulsion polymerization.

Synthesis and characterization of graft copolymers with poly(epichlorohydrin-co-ethylene oxide) as backbone by combination of ring-opening polymerization with living anionic polymerization

Series of graft copolymers with [Poly(epichlorohydrin-co-ethylene oxide)] [Poly(ECH-co-EO)] as backbone and polystyrene (PS), poly(isoprene) (PI) or their block copolymers as side chains were successfully synthesized by combination of ring-opening polymerization (ROP) with living anionic polymerization. The Poly(ECH-co-EO) with high molecular weight (Mn = 3.3 × 104 g/mol) and low polydispersity index (PDI = 1.34) was firstly synthesized by ring-ROP using ethylene glycol potassium as initiator and triisobutylaluminium (i-Bu3Al) as activator. Subsequently, by “grafting onto” strategy, the graft copolymers Poly(ECH-co-EO)-g-PI, Poly(ECH-co-EO)-g-PS and Poly(ECH-co-EO)-g-(PI-b-PS) were obtained using the coupling reaction between living PI−Li+, PS−Li+ or PS-b-PI−Li+ species capped with or without 1,1-diphenylethylene (DPE) agent and chloromethyl groups on poly(ECH-co-EO). By model experiment, the addition of DPE agent was confirmed to have an important effect on the grafting efficiency at room temperature. Finally, the target graft copolymers and intermediates were characterized by SEC, 1H NMR, MALLS and FTIR in detail, and thermal behaviours of the graft copolymers were also investigated by DSC measurement.

The Effect of Process Factors to the Kinetic Studies of Emulsion Copolymerization of Natural Rubber and Styrene

Graft copolymer of styrene on natural rubber was prepared in laboratory by emulsion polymerization using potassium persulfate and sodium laurysulfate as an initiator and an emulsifier, respectively. The concentrations of initiator and emulsifier were varied in the range of 0.7 to 2.0 parts and 5.0 to 11.0 part per 100 parts of organic compositions, respectively. The gross polymers were purified by soxhlet extraction to remove ungrafted polystyrene and ungrafted natural rubber to obtain the graft copolymer (NR-g-PS). Characterization of graft copolymer was confirmed by FTIR spectroscopy. The results of the conversion, the kinetic rate of polymerization and grafting efficiency as a function of initiator and emulsifier concentration were studied. It was found that the conversion and the rate of polymerization increased with initiator and emulsifier concentration. At 1.0 parts of initiator and 5.0 parts of emulsifier were the optimum values. Therefore, the conversion and grafting efficiency can be used to predict the reaction conditions as a guideline for the graft copolymer production in pre-scale up reactor.

Preparation and Characterization of Graft Copolymer of Acryloyloxyethyl-Trimethylammonium Chloride and Starch

Using ammonium persulfate (APS) as the initiator, a series of cationic starch— acyrloxyethyl-trimethylammonium chloride (DAC) graft copolymers containing quaternary ammonium groups were prepared in aqueous solution. The results showed that the cationic graft copolymer of high cationic degree (DC) could be obtained in this reaction system. The maximum DC of 53.68% was achieved with ASP/starch mass percentage 1.0%, m(DAC):m(starch) = 2.5,at 50°C and reaction time 8h. Structures of the graft copolymers were characterized by FTIR, scanning electron microscope (SEM) and thermo-gravimetric/differential thermal analyze (TG-DTA).

Synthesis, characterization, and application of amylopectin‐graft‐poly(AM‐co‐AMPS)

AbstractA series of graft copolymers poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonic acid) [Ap‐g‐p(AM‐co‐AMPS)] have been synthesized by graft copolymerization of amylopectin (Ap) with acrylamide (AM) and 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS). The copolymerization has been carried out by solution polymerization technique and using ceric ammonium nitrate (CAN) as initiator. The characterization of graft copolymer has been carried out by elemental analysis fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and scanning electron microscopy (SEM). The effects of reaction conditions on graft copolymerization and the use of the copolymer as flocculating agent in kaolin suspension have been investigated. Experiments have shown that graft copolymer with higher grafting level, higher intrinsic viscosity, and higher anionic degree can be obtained by changing the method of addition of monomers and by controlling the ratio of AMPS and AM. The flocculation performances have been investigated through jar test method, and it has been observed that the graft copolymer with molar ratio of 2 : 1 of AM and AMPS shows best performance in flocculating kaolin suspension. Metal ion sorption study with Cu2+ has shown that the graft copolymer absorbs Cu2+ efficiently. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthesis and characterization of grafted carboxymethyl guar gum

AbstractGraft copolymers of carboxymethyl guar gum (CMGG) and polyacrylamide (PAM) have been synthesized by grafting polyacrylamide chains onto carboxymethyl guar gum backbone using a ceric‐ion‐induced solution polymerization technique. By varying the amount of initiator, three different grades of graft copolymers are synthesized. The characterization of graft copolymer is carried out by FTIR, NMR, intrinsic viscosity measurement, SEM, SLS, DTG, and rheology. A comparison of flocculation efficiency of CMGG and its graft copolymer shows that the graft copolymer exhibits better flocculation performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis and characterization of graft copolymer of chitosan and polyethylene glycol

MPEG was modified with 1,1'-carbonyldiimidazole, then the activated MPEG reacted with primary amino groups of chitosan. Synthesize the graft copolymer of chitosan and polyethylene glycol in two steps. The structure of the copolymer was characterized by FT-IR and 1H-NMR. It agrees with the PEG content of classical stealth nanoparticles materials. The X-ray diffraction and DSC analysis proved that the crystallinity of the copolymer increased. It is a promising material for the stealth nanoparticles. It is a potential new carrier for the drug delivery systems of long-circulation and solid carcinoma.

Synthesis and characterization of graft copolymer (alginate-g-poly(N,N-dimethylacrylamide))

The graft copolymerization of N,N-dimethylacrylamide onto alginate by free radical polymerization using potassium peroxymonosulphate-sarbose as a redox pair in an inert atmosphere was investigated. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of N,N-dimethylacrylamide (7 × 10−2 mol/L to 23 × 10−2 mol/L), potassium peroxymonosulphate (2 × 10−3 mol/L to 18 × 10−3 mol/L), sarbose (0.4 × 10−3 mol/L to 3.4 × 10−3 mol/L), sulphuric acid (1 × 10−3 mol/L to 8 × 10−3 mol/L) and alginic acid (0.4 g/L to 1.8 g/L) along with time duration (60 min to 180 min) and temperature (25°C to 45°C). Water swelling capacity, metal ion sorption and flocculation studies of the synthesized graft copolymer have been performed. The graft copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis.

Radiation-Induced Graft Copolymerization of Metacrylic Acid and Butyl Methacrylate onto Poly(3-hydroxybutyrate)

Poly(3-hydroxybutyrate) (PHB) is a biocompatible and biodegradable thermoplastic polyester obtained microbiologically. Its main drawbacks are its thermal instability, brittleness, and moderate hydrophobicity, which limit its applications. The present study involves the chemical modification of PHB by means of the synthesis and characterization of graft copolymers with two selected monomers. Typical monomers, methacrylic acid (MA) and butyl methacrylate (BuM), were graft polymerized onto PHB by radiation-induced graft copolymerization reaction to improve PHB's hydrophilicity. The effect of different solvents on the radiation-induced graft copolymerization of the monomers onto poly(3-hydroxybutyrate) was investigated. Structures of the graft copolymers obtained were determined by Fourier transform-infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. Examination of the infrared spectra of the polymeric materials showed that there are no significant changes in their spectra apart from slight changes in the intensities of absorption bands. The results are consistent with the successful grafting of MA and BuM monomer onto PHB. Double melting peaks for grafted PHB were observed, which was probably caused by recrystallization of the graft copolymer. For grafted PHB, the introduction of MA and BuM groups hinders its crystallization, causing a decrease in the degree of crystallinity. The swelling behavior was also studied. The results showed that water uptake significantly increased. Hence, such a grafting process improved the hydrophilic character of PHB. The possibility of using these grafted polymers in practical biomedical applications is promising.

Preparation and Characterization of Graft Copolymer EVA-g-PU

Via melting graft reaction, a new type of graft copolymer EVA-g-PU was synthesized. The characterization of Fourier transform infrared and 13C -nuclear magnetic resonance indicated that the polyether-polyurethane prepolymer was grafted on the EVA main chain successfully. Differential scanning calorimetry testing showed that the melting temperature increased with the increase of PU prepolymer content. The enhanced storage modulus of EVA-g-PU was characterized by dynamic mechanical thermal analysis. The enhanced degree in the storage modulus of EVA-g-PU increased with the increase of PU prepolymer content. Thermal gravimetric analysis testing showed that thermal stabilities of EVA-g-PU increased with the increase of PU prepolymer content.