Synthesis Of Graft Copolymers Research Articles

Amphiphilic polymeric micelles originating from 1,4-β-D-glucan-g-polyphenylene oxide as the carriers for delivery of docetaxel and the corresponding release behaviors

A novel amphiphilic polymeric drug carrier was synthesized through grafting polymerization of water-soluble 1,4-β-D-glucan from cotton cellulose tailored and polypropylene oxide (PPO), and then use thereof to synthesize graft copolymer 1,4-β-D-glucan-PPO-docetaxel (DTX). The products were characterized by FTIR, 1H NMR, and 13C NMR. The physicochemical characteristics of 1,4-β-D-glucan-PPO and 1,4-β-D-glucan-PPO-DTX such as molecular weight distribution (MWD), micro-morphology, size, critical micelle concentration (CMC), aggregation number of micelle (N), in vitro stability and drug pharmacokinetic study in vivo were investigated. The results reveal that the degree of polymerization (DP) of the water-soluble 1,4-β-D-glucan from cotton cellulose tailored is equal to 7; the 1,4-β-D-glucan-PPO surfactant possesses good surface activity while the adduct number of propylene oxide reaches appropriately to 20; the DTX is completely dispersed in water medium with 1,4-β-D-glucan-PPO-DTX micelle and the drug conjugated percent is up to 40.3%; In vitro study confirms that 1,4-β-D-glucan-PPO-DTX has the capacity for sustained drug release; In plasma, 1,4-β-D-glucan-PPO-DTX exhibits a significantly enhanced Cmax, AUC(0-t) and T1/2 compared with DTX. These results demonstrate that 1,4-β-D-glucan-PPO has the potential to be used as a novel biocompatible biomaterial for drug delivery.

Synthesis and Characterization of Butyl Acrylate-based Graft Polymers with Thermo-responsive Branching Sites via the Diels-Alder Reaction of Furan/Maleimide

Thermo-responsive butyl acrylate/furfuryl methacrylate copolymer-based (PBF backbone) graft (co)polymers with dynamic covalent linkages between their backbones and side chains via the Diels-Alder reaction of furan/maleimide were synthesized. Atom transfer radical polymerization (ATRP) was used to synthesize graft copolymers with thermo-responsive transformation from graft copolymers to linear polymers with bimodal or wide MWD. The NMR measurements indicated that the Diels-Alder reaction and retro-Diels-Alder reaction occurred, depending on the change of the temperature, meaning that the side chains could be cleaved and reformed according to the variation of the temperature. GPC measurements demonstrated that the molecular weights of the polymers were thermoresponsive. Furthermore, three graft copolymers with various branching chains (PBF-g-PBA, PBF-g-P(BMA-co-MA) and PBF-g-PBMA) were compared to study the influence of compatibility between the backbone and the branching chain on the efficiency of Diels-Alder reaction after the cleavage of the DA linkage. The results showed that the ability of the side chains to come back to the main chain was strongly affected by the compatibility between the backbone and the side chains and the flexibility of the polymer chains.

Synthesis of Highly Defined Graft Copolymers Using a Cyclic Acetal Moiety as a Two-Stage Latent Initiating Site for Successive Living Cationic Polymerization and Ring-Opening Anionic Polymerization

The synthesis of well-defined graft copolymers with designed intervals between branches was achieved using cyclic acetal moieties as two-stage latent initiating sites. A cyclic acetal was shown to initiate the living cationic polymerization of vinyl ethers (VEs), yielding a polymer with a hydroxy group at the α-end derived from the cyclic acetal. The newly generated hydroxy group was able to efficiently induce the subsequent ring-opening anionic polymerization of l-lactide (LLA), and a diblock copolymer with a narrow molecular weight distribution (MWD) was obtained. For the synthesis of a graft copolymer, a five-membered cyclic acetal moiety was introduced at the ω-chain ends of poly(VE)s, which was employed as the initiating site for the living cationic polymerization of VEs. Repeated polymerization and acetalization generated a macroinitiator with several hydroxy groups on the side chain of a poly(VE) backbone. Graft copolymers possessing branches with narrow MWDs and regular spaces between the branches...

Synthesis and Properties of Adhesive Polymer-Methylmethacrylate Materials

Kinetics of emulsion polymerization of hydrophilic vinyl monomers in the presence of polyvinylpyrrolidone and technological principles of their synthesis are determined. Reasonable technological parameters in the synthesis of copolymers are determined. Physicochemical properties of the synthesized copolymers (surface tension, the size of latex particles, and pH) are determined. Synthesized graft copolymers were used to create high-adhesion polymer-monomer compositions. These compositions have high reactivity at room temperature. It can be regulated by the nature of the polymer matrix and the introduction of comonomers and fillers due to the influence of physicochemical factors on the process of polymer formation. The rate of polymerization and the degree of monomer conversion largely depend on the nature of the polymer matrix. The highest polymerization rate and the maximum degree of conversion are observed when using a copolymer of polyvinylpyrrolidone and polymethylmethacrylate. Materials based on the developed compositions are characterized by a low residual monomer content and high operational properties, such as surface hardness, Vicat softening temperature, and adhesive bond strength to supports of different nature.

Chemoenzymatic synthesis of dual-responsive graft copolymers for drug delivery: long-term stability, high loading and cell selectivity.

A series of amphiphilic graft copolymers, poly(N-propargyldiethanolamine 4,4'-dithiodibutyionate)-graft-monomethoxy poly(ethylene glycol) (PPD-g-mPEG), were designed via a chemoenzymatic method for pH and reduced glutathione (GSH) dual-responsive drug delivery. The effects of percent grafting and molecular weights of mPEG on critical micelle concentration (CMC) values, size of micelles, drug loading and dual-response were tested. The graft copolymers could easily form homogeneous spherical micelles with appropriate sizes and zeta-potentials. The micelles of PPD-g-mPEG copolymers loaded doxorubicin (DOX) in high efficiency, and showed excellent stability under physiological conditions and synergetic dual-response to weakly acidic pH and GSH. In vitro experiments confirmed that the DOX-loaded micelles could be internalized into cancer cells efficiently and release DOX over time. Furthermore, cell cytotoxicity assays indicated that the graft copolymers were non-cytotoxic to both cancerous and normal cells while the DOX-loaded micelles greatly improved the selectivity ratios between HeLa cells and HL-7702 cells. DOX-loaded micelles also avoided hemolysis of red blood cells (RBCs) effectively compared with commercialized doxorubicin hydrochloride. All these demonstrated the potential of PPD-g-mPEG as a model to create more functional dual-responsive nanocarriers for controlled drug delivery.

Moringa gum-g-poly(N-vinyl-2-pyrrolidone) – a potential buccoadhesive polymer

In the present study, MG-g-poly(NVP) was synthesized using microwave-assisted graft co-polymerization reaction. Synthesis of graft co-polymer was optimized using response surface methodology. The influence of concentration of Moringa gum, N-vinyl-2-pyrrolidone and ammonium persulfate on grafting efficiency of graft copolymer was studied using 3-factor, 3-level central composite experimental design. The optimal calculated parameters were found to be concentration of Moringa gum-1% (w/v), N-vinyl-2-pyrrolidone-2% (w/v), and ammonium persulfate–10 mMol/L, which yielded a graft co-polymer of% grafting efficiency (24.23%). The graft co-polymer were further characterized by Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy studies. The results of characterization revealed that grafting of N-vinyl-2-pyrrolidone on Moringa gum decreases its crystallinity and makes its surface smoother. Graft copolymer was further evaluated for pharmaceutical application by formulating clotrimazole-loaded buccal discs. A comparative evaluation of buccal discs of graft co-polymer with native gum revealed higher ex-vivo bioadhesion time and greater sustained release effect of the graft copolymer than of native gum.

Benzodioxinone Photochemistry in Macromolecular Science: Progress, Challenges, and Opportunities.

This paper reviews the photoinduced reactions of benzodioxinones and how they function in polymer synthesis and UV curing applications. The mechanistic characteristics of the ketene and benzophenone production from the photolysis of benzodioxinone indicate that, under certain conditions, each intermediate may undergo further reactions expedient for the formation of various polymeric structures. While ketenes are efficient contributors to step-growth polymerization when subjected to reaction with the compounds possessing hydroxyl or amine groups, the released benzophenone can be utilized as a photoinitiator in both the free radical and cationic polymerizations. It has been shown that the photolysis of heterobifunctional monomers equipped with benzodioxinone and aliphatic hydroxyl groups leads to the formation of oligoesters with a narrow molecular weight distribution. We also validated the photochemical ability of benzodioxinone to induce the synthesis of block and graft copolymers, hybrid and branched polymers, and cross-linked monofunctional vinyl monomers or hydroxyl group-containing linear polymers.

Synthesis and Characterization of Polysulfone-based Graft Copolymer Possessing Quaternary Ammonium Salts via Photoiniferter Polymerization

A well-defined polysulfone-based graft copolymers containing quaternary ammonioum salts are successfully prepared by photoiniferter method under mild conditions. The corresponding macroiniferter agent is sequentially synthesized by chloromethylation and nucleophilic substitution reaction between obtained chloromethylated polysulfone and sodium diethyl dithiocarbamate. Upon UV irradiation, this macroiniferter enables the successful grafting of 2-(dimethylamino)ethyl methacrylate onto the polysulfone backbone in a controlled manner. After the successful synthesis of graft copolymers, the tertiary amine groups in the side-chains are readily quaternized using methyl iodide to get desired quaternary ammonioum salts containing graft copolymers.

Facilitated olefin transport through membranes consisting of partially polarized silver nanoparticles and PEMA-g-PPG graft copolymer

We report the preparation of solid-state facilitated olefin transport membranes based on a low-cost, one-pot, room-temperature synthesized graft copolymer, i.e., poly(ethylene-alt-maleic anhydride)-g-O-(2-aminopropyl)-O′-(2-methoxyethyl) polypropylene glycol (PEMA-g-PPG). An electron acceptor, 7,7,8,8-tetracyanoquinodimethane (TCNQ), was employed to activate the surface of the silver nanoparticles (AgNPs), leading to partial polarization. The AgNPs interacted with TCNQ as well as the PEMA-g-PPG graft copolymer to form facilitated olefin transport membranes, as characterized by Fourier transform infrared spectroscopy, UV–vis spectroscopy, and X-ray photoelectron spectroscopy. The PEMA-g-PPG/AgNP membrane activated by TCNQ showed long-term stability (with a mixed gas permeance of 7.8 GPU and propylene/propane selectivity of 17.5) of up to 100h, while that without TCNQ showed poor stability. The membrane based on PEMA-g-PPG showed better performance than those based on conventional matrices of poly(ethylene oxide) (PEO), poly(vinyl pyrrolidone) (PVP), or poly(ether-block-amide) (PEBAX).

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.

Synthesis, Characterization and Flocculation Characteristics of Polysaccharide Graft Copolymers

Research & Development in Material Science Synthesis, Characterization and Flocculation Characteristics of Polysaccharide Graft Copolymers Karmakar GP* Department of Mining Engineering, Indian Institute of Technology, India *Corresponding author: Karmakar GP, Department of Mining Engineering, Indian Institute of Technology, Kharagpur-721302, India Submission: September 09, 2017; Published: October 16, 2017 DOI: 10.31031/RDMS.2017.01.000516 ISSN : 2576-8840Volume1 Issue4

Modifications of Hydroxyl-Functionalized HEA/HEMA and Their Polymers in the Synthesis of Functional and Graft Copolymers

Background: Functional groups have played a fundamental role in synthesis of polymers due to they decide about polymerization methods, and influence on their topologies, properties and applications. The functional polymers are used as a high-performance materials with well-adjusted properties by modification of functionalities that can be addressed selectively to a variety of applications, usually in biomedical field. Objective: In this minireview article hydroxy-functionalized polymers, mostly based on 2-hydroxyethyl methacrylate (HEMA) or 2-hydroxyethyl acrylate (HEA), are discussed as products of the controlled polymerizations and as substrates in the functionalization reactions. Conclusion: The hydroxyl group gives opportunity for prepolymerization reactions, including protection group and macromonomer preparation. Multifunctional (co)polymers of HEMA/HEA contain reactive hydroxyl groups, which are directly accessible or caring suitable protective groups that can be removed or/and modified by post-polymerization reactions. The variation of approaches let to obtain functional polymers with linear, star-shape and graft topologies as the well-defined structures for the advanced functional materials, including smart polymeric devices.

Synthesis and characterization of maleylated cellulose-g-polyacrylamide hydrogel using TiO2 nanoparticles under sunlight

Graft polymerization onto the cellulose is one way to produce semisynthetic copolymers and semiconductors were hardly used as initiators. Maleylated cellulose (MC) with different degree of carboxyl groups was synthesized and degree of carboxyl groups was determined using titration method. Then the graft copolymers of acrylamide (AM) on MC were synthesized by titanium dioxide semiconductor photoinitiator in aqueous suspension under sunlight. The effect of different parameters, such as the degree of carboxyl groups, degassing of atmosphere, reactor type, light source, MC/AM ratio, and initiator concentration, was evaluated in the synthesis of graft copolymers. MC with a high degree of carboxyl groups about 2.8 mmol g−1 was selected for graft photopolymerization. Maximum monomer conversion (55%) for Maleylated cellulose-g-polyacrylamide (MC-g-PAM) was achieved with 0.5 mg TiO2, MC/AM = 0.056, argon atmosphere, sunlight source, and double quartz tube reactor. The maximum amount of equilibrium swelling (41 g g−1) was achieved for MC-g-PAM with 34% monomer conversion. The resulting graft copolymers were characterized by FT-IR, SEM, and TGA. Synthesis of MC-g-PAM using TiO2 nanoparticles (NPs) as the initiator was done successfully that shows the TiO2 NPs are useable in graft polymerization of acrylamide monomers onto the MC under sunlight.

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 of xanthan gum graft copolymer and its application for controlled release of highly water soluble Levofloxacin drug in aqueous medium

Graft copolymers (XG-g-PNVP-1 to XG-g-PNVP-5) of xanthan gum (XG) and poly(N-vinyl-2-pyrrolidone) (PNVP) was synthesized by free radical polymerization using peroxymonosulphate/thiourea redox pair. The synthesized graft copolymers were well characterized by 1H NMR, FTIR, XRD, SEM, TGA/DTA and AFM analyses. The optimum conditions for maximum grafting were determined by varying the concentrations of N-vinyl-2-pyrrolidone (NVP) from 10×10−2 to 18×10−2moldm−3; the grafting ratios increases up to 14×10−2moldm−3, while thereafter decreased. Graft copolymer (XG-g-PNVP-D) hybrid was prepared to load levofloxacin drug, about 15mg drug was loaded; and its release was studied in phosphate buffer solution (PBS) at pH 7.4 on 37±0.1°C; About 80% drug was released in 36h.

Synthesis of graft copolymers based on hyaluronan and poly(3-hydroxyalkanoates)

This work reports the synthesis and characterisation of new amphiphilic hyaluronan (HA) grafted with poly(3-hydroxyalkanoates) (PHAs) conjugates. Hydrolytic depolymerisation of PHAs was used for the synthesis of defined oligo(3-hydroxyalkanoates)-containing carboxylic terminal moieties. A kinetic study of the depolymerisation was followed to prepare oligomers of required molecular weight. PHAs were coupled with hydroxyl groups of HA mediated by N, N′-carbonyldiimidazole (CDI) or HSTU Tetramethyl-O-(N-succinimidyl) uronium hexafluorophosphate. For the first time, the covalent bonding of oligo derivatives of P(3-hydroxybutyrate), P(3-hydroxyoctanoate), P(3-hydroxyoctanoate-co-3-hydroxydecanoate) and P(3-hydroxyoctanoate-co-3-hydroxydecanoate-co-3-hydroxydodecanoate) and HA was achieved by “grafting to” strategy. Achieved grafting degree was a function of hydrophobicity of PHA, Mw and polarity of the solvent. The most suitable reaction conditions were observed for oligo (3-hydroxybutyrate) grafted to HA (grafting degree of 14%). Graft copolymers were characterized by FT-IR, NMR, DSC and SEC-MALLS. Graft copolymers can be physically loaded with hydrophobic drugs and may serve as drug delivery system.

Effect of ferrocene on the synthesis of graft copolymers of vinylpolysiloxane and styrene

The effect of ferrocene on the synthesis of graft poly(dimethylsiloxanes) by radical copolymerization of a polysiloxane containing terminal trivinylsiloxy groups with styrene. The backbone in the synthesized graft copolymers is formed by a linear poly(dimethylsiloxane) with a part of its vinyl groups involved in grafting polystyrene chains. The products were studied by gel permeation chromatography, 1Н NMR spectroscopy, and optical microscopy.

Synthesis and Thermoresponsive Behaviors of Thermo-, pH-, CO2-, and Oxidation-Responsive Linear and Cyclic Graft Copolymers

Rational macromolecular design allows us to construct multiresponsive architectural polymers with a potential toward multipurpose applications. This study aims at synthesis and LCST-type thermoresponsive behaviors of multisensitive linear and cyclic graft copolymers with polyacrylamide backbone and hydrophilic PEG grafts. The cloud point could be tuned by many factors, and the effect of cyclization was confirmed by the elevated cloud point in H2O up to 12.8 °C under same conditions. The PEG-connecting Y junctions with dual amide, thioether, and tertiary amine groups allowed thermo-, solvent-, pH-, and CO2-switchable inter/intramolecular hydrogen bonding interactions and hence resulted in unusual solvent (H2O or D2O) and pH (about 6.8–8.5) dependent phase transition and irreversible CO2-responsive behavior. Meanwhile, the solution blending could lead to one or two phase transition(s) dependent on types and compositions of the blends. The meticulous introduction of multifunctional Y junctions into graft cop...

Synthesis and characterization of graft copolymers of chitosan with NIPAM and binary monomers for removal of Cr(VI), Cu(II) and Fe(II) metal ions from aqueous solutions

To develop pH responsive hydrogels, N-isopropylacrylamide (NIPAM) has been grafted on to chitosan by free radical initiation method using azoisobutrylnitrile (AIBN) as an initiator. The optimum grafting conditions were worked out for grafting of NIPAM onto 1g of chitosan by varying one reaction parameter at a time and keeping all other parameters constant. Binary monomers were grafted for five different concentrations of comonomers acrylic acid (AAc), acrylamide (AAm) and acrylonitrile (AN) at optimum grafting conditions evaluated for GMA alone onto chitosan. The grafted copolymers were analyzed by FTIR, TGA/DTA, XRD and SEM. The swelling studies for the grafted samples were performed at various pH in order to explore their end use in sorption of Cr(VI), Fe(II) and Cu(II) ions from water system. Metal ion sorption behaviour of polymeric samples was studied as function of time, temperature and pH. Various metal ion sorption parameters such as percent uptake (Pu), partition coefficient (Kd) and retention capacity (Qr) were discussed. Chitosan grafted with binary monomers NIPAM-co-AAc and NIPAM-co-AAm showed best results for sorption of all three metal ions.

Synthesis of grafted poly(p-phenyleneethynylene) via ARGET ATRP: Towards nonaggregating and photoluminescence materials

In this paper, the synthesis and characterisation of photoluminescent graft copolymers of poly(p-phenyleneethynylene) (PPE) with grafted poly(n-butyl acrylate) (PnBA) side chains is presented. The grafted copolymer exhibited the desired intrinsic physical properties of the grafted side chain polymer while preserving the optical properties of PPE. Grafting from the conjugated macroinitiator was conducted utilising activators regenerated by an electron transfer (ARGET) atom transfer radical polymerisation (ATRP) technique. The novel physical and optical properties of the grafted copolymer are reported and the enhancement of the quantum yield both in the solid and solution state can be attributed to the prevention of interchain interactions of the PPE chains. The enhancement of the photophysical properties observed upon grafting is greater than that seen in a similar PPV system.