Alok K. Chatterjee

Visible light-induced surface initiated atom transfer radical polymerization of methyl methacrylate on titania/reduced graphene oxide nanocomposite

A novel visible light assisted photoredox catalyst system for surface initiated atom transfer radical polymerization (SI-ATRP) is developed for polymer growth on the surface of titania/reduced graphene oxide (TiO2/rGO) nanocomposites using tetrasulfonated copper(II) phthalocyanine (CuPcS) as catalyst at ambient temperature. The synthesized composite was initially treated with 3-aminopropyltrimethoxysilane (APTMS), and then functionalized with 2-bromoisobutyryl bromide (BIBB) moieties, serving as a surface initiator for ATRP. In the present method, TiO2/rGO acted as a photoactive material to reduce Cu(II) to a Cu(I) complex under visible light by a one-electron transfer process as well as a surface for ATRP initiator immobilization and gave polymer linked TiO2/rGO composites. These hybrid materials were found to show high dispersability in organic solvents.

Conventional and atom transfer radical copolymerization of n-octyl acrylate-styrene: chemoselectivity and monomer sequence distribution by 1H NMR

Abstract Octyl acrylate and styrene (OA–St) were copolymerized by conventional polymerization at 80 °C and atom transfer radical polymerizations at 130 °C in different feed ratios (0.1–0.9 mole fraction of OA) using benzoyl peroxide and cuprous chloride/2,2′-bipyridine/1-phenyl ethyl chloride respectively. Two linear (Fineman–Ross, Kelen–Tudos) methods and a nonlinear least-squares method were employed for determination of monomer reactivity ratios (rOA=0.30±0.02 and rSt=0.69±0.04). Integrated intensities of the three peaks observed in the 1 H NMR spectra of –OCH2 group (3.2–4.2 ppm) were used to determine the mole fraction of 111, 112 or 211 and 212 triad sequences in the copolymers. In addition, the rOA value was used for theoretical determination of mole fraction of these triad sequences. Well-agreed theoretical and experimental values helped us in determining most probable mole fractions of the triad sequences of monomers.

Docosyl acrylate modified polyacrylic acid: synthesis and crystallinity

Abstract Copolymers of n-docosyl acrylate and acrylic acid were synthesized in tetrahydrofuran by conventional free radical polymerization using benzoyl peroxide as initiator. The increase in crystallinity of the copolymers with increasing C22 acrylate mole fraction was studied. It was found that even with very low mole fraction of C22 acrylate (0.14) in the polymer chain the copolymers shows significant crystallinity (crystallinity fraction 0.23 against 0.52 for homopolymer of C22 acrylate).

Expanded corn starch a novel material as macroinitiator/solid support in SI and AGET ATRP: GMA polymerization

Here we have shown the use of expanded corn starch (ECS) as an effective macro-initiator in Surface Initiated Atom Transfer Radical Polymerization (SI-ATRP) as well as a solid support in catalytic system for Activators Generated by Electron Transfer-Atom Transfer Radical Polymerization (AGET ATRP) for poly-glycidyl methacrylate (PGMA) with reasonably narrow polydispersity (PDI: 1.3–1.6). ECS having characteristic V type crystallinity imparts high surface area (~50 m2g−1), pore volume (0.43 cm3g−1) and high thermal stability enabling it as a better material over CS for use in ATRP. Also, catalytic system in AGET ATRP based on ECS can be recycled for several times without substantial loss of activity. Thus, ECS proves to be a versatile material that can be used in different ways in ATRP leading to polymers/polymer-hybrids with controlled molecular weight.

Note High Yield Synthesis of Low Molecular Weight Poly(Vinyl Acetate) in Aqueous Acidic Media

Abstract Polymerization of vinyl acetate continues to interest workers in the field as evidenced by recent publications [1–3]. However, little information is available concerning the synthesis of low molecular weight poly(vinyl acetate) (PVAc) despite its industrial importance.