Biological macromolecule chitosan grafted co-polymeric composite: bio-adsorption probe on cationic dyes

Chitosan biological macromolecule is a versatile polymer; chemical modification has been carried out that lead to the formation of chitosan grafted polymers composites (Chito-g-PC). We proposed synthesis of six various Chito-g-PC as sorbents for toxic dyes. A novel graft copolymerization method based on radical polymerization with vinyl monomer like acrylic acid, acrylamide, N-isopropylacrylamide, methacrylic acid and polyacrylonitrile were utilized in order to address the large amount of swelling at four different pH buffers solution. The effect of initiator and monomer concentration, time and temperature on % grafting and % grafting efficiency were performed. Comparative characterization of Chito and Chito-g-PC were evaluated by SEM, XRD and FTIR, as well as solubility characteristics of the composites were determined by various pH buffer solution. Cationic toxic dyes Malachite green (MG) and Methylene blue (MB) were selected as the sorbet, and Chito-g-PC were used as biosorbents. Thermodynamic analysis showed that the sorption process was spontaneous and endothermic with an increased randomness. The sorption experiments were realized with six different Chito-g-PC for MG and MB at various pH.

Hybrid Copolymerization of Ethylene Oxide and tert-Butyl Methacrylate with Organocatalyst

Hybrid copolymerization of structurally different, reactivity and mechanism distinct monomers (e.g., cyclic and vinyl type monomers) is of great interest and challenge for both academic research and practical application. Herein, ethylene oxide-co-tert-butyl methacrylate-co-poly(ethylene glycol) benzyl methacrylate (EO-co-BMA-co-bPEO), a statistical copolymer was synthesized via hybrid copolymerization of EO and BMA using an uncharged, non-nucleophilic organobase t-BuP4 as the catalyst. Detailed characterizations indicate that hybrid copolymerization of ethylene oxide and vinyl monomer forms a statistical copolymer concurrently with the transesterification of tert-butyl group and oligomer PEO anions. The application of the copolymer as all solid lithium-ion battery polymer electrolyte was investigated by detecting the ionic conductivity (σ) with electrical impedance spectrum measurement.

Ultraflexible and Mechanically Strong Polymer/Polyaniline Conductive Interpenetrating Nanocomposite via In Situ Polymerization of Vinyl Monomer

Simultaneous enhancement of conductivity and mechanical properties for polyaniline/polymer nanocomposite still remains a big challenge. Here, a reverse approach via in situ polymerization (RIP) of vinyl monomers in waterborne polyaniline dispersion was raised to prepare conductive polyaniline (GPANI)/polyacrylate (PMB) interpenetrating polymer (GPANI-PMB) nanocomposite. GPANI/PMB physical blend was simultaneously prepared as reference. The conductive GPANI-PMB nanocomposite film with compact pomegranate-shape morphology is homogeneous, ultraflexible and mechanically strong. With incorporating a considerable amount of PMB into GPANI via the RIP method, only a slight decrease from 3.21 to 2.80 S/cm was detected for the conductivity of GPANI-PMB, while the tensile strength significantly increased from 25 to 43.5 MPa, and the elongation at break increased from 40% to 234%. The water absorption of GPANI-PMB3 after 72 h immersion decreased from 24.68% to 10.35% in comparison with GPANI, which is also higher than that of GPANI/PMB. The conductivity and tensile strength of GPANI-PMB were also much higher than that of GPANI/PMB (0.006 S/cm vs. 5.59 MPa). Moreover, the conductivity of GPANI-PMB remained almost invariable after folding 200 times, while that of GPANI/PMB decreased by almost half. This RIP approach should be applicable for preparing conventional conductive polymer nanocomposite with high conductivity, high strength and high flexibility.

Synthesis of Biodegradable Aloevera-acrylic Acid Based Hydrogel With Enhanced Water Retention Capacity and Its Impact on Agriculture

The present work deals with the synthesis of biodegradable hydrogel using a natural polysaccharide Aloevera and vinyl monomer acrylic acid. In this synthesis, ammonium per sulphate was used as an initiator and glutaraldehyde as cross-linker, acrylic acid was used as monomers and Aloevera as backbone. Grafting was confirmed by different techniques like SEM, FT-IR, XRD and EDS. Maximum percentage swelling of synthesized hydrogel was found to be 796 %. Biodegradation behavior of Av-cl-poly(AA) was studied by soil burial, compositing and vermicompositing method. Maximum biodegradation was found to be 90%, 94% and 93% in case of soil burial, composting and vermicomposting methods, respectively. Biodegradation of Av-cl-poly(AA) was confirmed by FTIR and SEM techniques. Water retention capacity was prolonged from 11days to 20 days using synthesized Av-cl-poly(AA). Water content of clay soil and sandy loam soil was increased to an extent of 6.1% and 5.79%, respectively.

Synthesis and Aggregation-Induced Emission Feature of Series of Polysiloxanes Containing Triphenylpyrrole Side-Chain

A series of aggregation-induced emission (AIE) active polysiloxanes (P7-1~P7-2, P29-1~P29-6) were prepared through hydrosilylation between polymethylhydrosiloxane (PMHS, DP=7 or 29) and AIE-active vinyl monomer 1-(4'-allyloxy-biphenyl)-2,5-diphenyl pyrrole (M-TPP), or with optical active monomer cholesteryl allyloxy ether (M-Chol*). Monomer M-TPP and all of the polymers exhibits aggeragation-induced emission enhancement properties. The fluorescence intensity of M-TPP in THF/H2O mixtures increases when the water fraction is higher than 60%, while is over 20% for polysiloxanes, which mainly because the entanglement of the flexible polysiloxane main-chain can restrict the molecular motion of triphenylpyrrole (TPP) derivates and induce the increasing of the fluorescence intensity. Moreover, the maximum relative fluorescence intensity (I/I0) is equal to 4 for M-TPP and 1.4~4.9 for polysiloxanes, and the grafted degree of the TPP derivative has effect on the AIE properties of polymers. The specific optical rotations of the chiral polymers increase with increasing the content of chiral cholesteryl ether moieties. All the target polymers possess good thermal stabilities and their decomposition points (Td) are greater than 320°C.

Effect of acryloylation on superabsorbency of starch copolymers

Starch is acryloylated and copolymerised without incorporating any vinyl monomer such as acrylic acid or acrylonitrile monomers to produce a superabsorbent copolymer. Fenton’s initiation system was used to produce polyacryloylated starch ester with varying degree of substitution. The copolymer from starch ester exhibited improved solubility, and an impressive water, saline, and solvents uptake. The superabsorbency of the samples is affected by the number of acryloyl groups on starch backbone. The starch ester with degree of substitution 0.8 had the highest water absorbency (102 g/g) in this experiment. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric (TGA) analyses were used to characterize the products.