Homopolymer Percentage Research Articles

EVALUATION OF IN-VITRO ANTIMICROBIAL ANTIOXIDANT AND ANTICANCER ACTIVITY OF A NEW CARBOXYMETHYLCHITOSAN-BASED CYANOGUANIDINE COPOLYMER

A new carboxymethylchitosan-based acryloylcyanoguanidine copolymer (CMCS-g-ACG) has been successfully prepared using the grafting technique. The grafting percentage, grafting efficiency, and homopolymer percentage were 86, 85, and 14%, respectively. The chemical structure and surface morphology of the CMCS-g-ACG copolymer were confirmed using elemental analysis, FTIR, 1H-NMR, XRD, and SEM. The copolymer has greater inhibition activity on both Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) in comparison to CMCS. It is more potent against E. coli than S. aureus. At 2000 μg/mL concentration, CMCS and the copolymer exhibited DPPH scavenging of 63.45% ± 4.19 and 78.56% ± 4.61, respectively. The copolymer of concentration less than 62.5 μg/mL was safe on the normal human lung fibroblast cells. The growth inhibition of the breast cancer cells at 500 μg/mL was 79.59% ± 2.12 and 91.41% ± 2.34 for CMCS and the copolymer, respectively. Thus, the insertion of ACG into CMCS highly boosted its antimicrobial, antioxidant and anticancer characteristics. It is a proper strategy to realize good systems to compete the traditional drugs used for such applications.

Antimicrobial and swelling behaviors of novel biodegradable corn starch grafted/poly(4-acrylamidobenzoic acid) copolymers

Novel antimicrobial copolymers resulted from free radical copolymerization of gelatinized corn starch in aqueous solution with different amounts of 4-acrylamidobenzoic acid monomer using ammonium persulfate (APS)/sodium bisulfite (NaHSO3) as a redox initiator. The grafting copolymerization was evidenced by FTIR, 1HNMR, scanning electron microscopy (SEM) and X-ray diffraction. The thermal stability was improved after the grafting reaction as detected from IPDT values calculated from the thermogravimetric analysis. The effect of changing grafting parameters (initiator concentration, monomer concentration, reaction time and temperature) on graft copolymerization were studied by measuring the grafting percentage (%G), grafting efficiency (%GE) and homopolymer percentage (%H). The optimum grafting conditions were determined as follows: Initiator concentration [I] = 3 × 10-2 mol/L, monomer concentration [M] = 0.25 mol/L, reaction temperature = 65 °C and reaction time = 2 h. The prepared copolymers exhibited swelling ability in both water and 0.9% saline solution. The antimicrobial study revealed a high degree of inhibition against different strains of Gram-positive bacteria, Gram-negative bacteria and fungi when compared with neat starch.

A study toward the physicochemical properties of graft copolymer (partially carboxymethylated guar gum‐g‐N,N′‐dimethylacrylamide): Synthesis and characterization

AbstractUnreported graft copolymer of N,N′‐dimethylacrylamide (DMA) with partially carboxymethylated guar gum (CmgOH) has been synthesized and the reaction conditions have been optimized for affording maximum grafting using a potassium peroxymonosulphate (PMS)/thiourea (TU) redox initiators under nitrogen atmosphere. The study of graft copolymerization has been performed to observe maximum value of grafting parameters except percentage of homopolymer by varying the concentrations of DMA, PMS, and TU. The grafting parameters increase continuously on increasing the concentration of DMA from 8 × 10−2 to 24 × 10−2 mol dm−3, PMS from 5 × 10−3 to 21 × 10−3 mol dm−3, and TU from 1.6 × 10−3 to 4.8 × 10−3 mol dm−3. The optimum temperature and time for grafting of DMA onto CmgOH were found to be 35°C and 120 min, respectively. The water‐swelling capacity of graft copolymer is investigated. Flocculation property for both coking and noncoking coals is studied for the treatment of coal mine waste water. The graft copolymer is characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis and characterization of xanthan gum‐g‐N‐vinyl formamide with a potassium monopersulfate/Ag(I) system

AbstractA xanthan gum‐g‐N‐vinyl formamide graft copolymer was synthesized through the graft copolymerization of N‐vinyl formamide (NVF) onto xanthan gum with an efficient system, that is, potassium monopersulfate (PMS)/Ag(I) in an aqueous medium. The effects of the concentrations of Ag(I), PMS (KHSO5), hydrogen ion, xanthan gum, and NVF along with the time and temperature on the graft copolymerization were studied by the determination of the grafting parameters (grafting ratio, add‐on, conversion, grafting efficiency, and homopolymer) and the rate of grafting. The maximum grafting ratio was obtained at a 0.6 g/dm3 concentration of xanthan gum. All the parameters showed an increasing trend with an increasing concentration of peroxymonosulfate, except the homopolymer percentage, which showed a decreasing trend. The grafting ratio, add‐on conversion, grafting efficiency, and rate of grafting increased with the concentration of Ag(I) increasing from 0.8 × 10−2 to 1.2 × 10−2 mol/dm3. The optimum time and temperature for the maximum degree of grafting were 90 min and 35°C, respectively. The graft copolymer was characterized with IR spectral analysis, thermogravimetric analysis, and differential calorimetry analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1637–1645, 2006

Study of graft copolymerization of N-maleamic acid-chitosan and butyl acrylate by γ-ray irradiation

N-maleamic acid-chitosan was synthesized and characterized by Fourier transform infrared spectra analysis (FT-IR) and 1H NMR. The graft copolymerization of N-maleamic acid-chitosan and butyl acrylate (BA) in acetic acid aqueous solution was investigated, using the γ-ray of 60Co γ-irradiation method. DSC (differential scanning calorimetry) trace of N-maleamic acid-chitosan-g-PBA has a glass-transition temperature ( T g) at −42 °C. The thermal stabilities of the graft copolymer were studied by the thermal gravimetric analysis (TGA). The effect of synthesis variables in the graft copolymerization have been discussed in the light of grafting efficiency, grafting percentage, and homopolymer percentage. Increasing grafting percentage was observed when the monomer concentration and total dose were increased or when the reaction temperature was decreased.

Study of radiation‐induced graft copolymerization of butyl acrylate onto chitosan in acetic acid aqueous solution

AbstractThe graft copolymerization of butyl acrylate onto chitosan in acetic acid aqueous solution was investigated, using the γ‐ray of 60Co γ‐irradiation method. Fourier transform infrared spectra analysis, X‐ray diffraction analysis, and scanning electron microscopy characterized the graft copolymer. The effect of synthesis variables in the graft copolymerization have been discussed in the light of grafting efficiency, grafting percentage, and homopolymer percentage. Hydrophilicity and impact strength of the films formed from copolymer solution were tested and their feasibility as seed coating was studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2855–2860, 2003

Ceric Ion-Initiated Grafting of Poly(Methyl Acrylate) onto Chitin

Abstract Poly(methy1 acrylate) was grafted onto chitin in an aqueous medium by using the ceric ion as a redox initiator in the presence of 10−4 M nitric acid and oxygen from the atmosphere. The grafting percentage turned out to be dependent on reaction temperature, time, and initiator concentration, but it was found to be independent of monomer concentration. In the course of the grafting reaction, homopolymerization of methyl acrylate occurs. The percentage of homopolymer was found to depend only on the reaction temperature. The apparent activation energy for the grafting reaction was estimated to be 11 kcal/mol. The grafted chitin is insoluble in solvents for chitin but shows enhanced swelling in some organic solvents.

Photochemical Grafting of Vinyl Monomers onto Starch

AbstractA general study of the UV light‐induced grafting of vinyl monomers upon potato starch is reported. A large variety of monomers with hydrophilic and hydrophobic properties and of initiators of free radicals was used. The best conditions of the grafting reaction were determined and several parameters were investigated: temperature, oxygen, initiator concentration, additives. Percentage of grafting‐time conversion curves, percentage of homopolymer, rate of grafting were obtained. For a given monomer, the most efficient photoinitiator can be selected.