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Early diagnosis of mastitis is essential to reduce the expenses it imparts on the dairy industry. Existing techniques fail to provide rapid and pathogen-specific information to direct the prescript...

The synthesis of polyethylene-graft-polystyrene copolymers by a multistep “grafting from” approach is described. In the first step, a bromo-functional polyethylene (PE-Br) was synthesized via ring-opening metathesis polymerization (ROMP) of cis-cyclooctene (COE) and quantitative hydrobromination. Subsequent irradiation of PE-Br under visible light in the presence of dimanganese decacarbonyl (Mn2(CO)10) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) resulted in the formation of TEMPO-substituted polyethylene (PE-TEMPO). Polystyrene (PS) chains were then grown via nitroxide mediated radical polymerization (NMRP) from the PE-TEMPO precursor to give desired PE-g-PS copolymers in a controlled manner. The intermediates at each step and final graft copolymers were characterized by 1H NMR, FT-IR, GPC, and DSC analyses.

A novel polymerization mechanism transformation strategy, combining ring-opening metathesis polymerization (ROMP) and visible light induced cationic polymerization, is successfully applied for the synthesis of polyethylene-graft-poly(cyclohexene oxide) (PE-g-PCHO). First, cis-cyclooctene (COE) was polymerized via ROMP in the presence of a chain transfer agent and quantitatively hydrobrominated to give bromo functional polyethylene (PE-Br). Subsequent irradiation of PE-Br in the visible range using dimanganese decacarbonyl (Mn-2(CO)(10)) and diphenyl iodonium hexafluorophosphate (Ph2I+PF6) as radical generator and oxidant, respectively, initiated cationic polymerization of cyclohexene oxide (CHO) resulting in the formation of PE-g-PCHO. The effect of irradiation time and Mn-2(CO)(10) concentration on the grafting density and efficiency was evaluated. Both the precursor polymers and the corresponding graft copolymers were characterized by H-1 NMR and Fourier transform infrared (FT-IR) spectroscopy, gel-permeation chromatography (GPC), and differential scanning calorimetric (DSC) analyses.

The recently developed photoinitiated atom transfer radical polymerization has been implemented in the inverse microemulsion polymerization of oligo(ethylene glycol) monomethyl ether methacrylate. Two different mechanisms including a simultaneous reverse and normal initiated ATRP and a combination of activators generated by electron transfer and initiators for continuous activator regeneration ATRP are investigated under UV light. The effects of various reaction parameters on the resulting particles have been systematically investigated, and it has been demonstrated that the particle size can be tuned based on UV light, initial stoichiometry, and aqueous phase fraction. The formed particles contained well-defined water-soluble polymers with relatively narrow molecular weight distribution (M-w/M-n < 1.4).

Visible light induced self-condensing vinyl polymerization is explored using 2-bromoethyl methacrylate (2-BEMA) and methyl methacrylate (MMA) as inimer and comonomer, respectively, in the presence of dimanganese decacarbonyl (Mn2(CO)10) for the preparation of hyperbranched polymers. Upon photoexcitation in the visible range, Mn2(CO)10 undergoes irreversible decomposition leading to the formation of initiating radicals through bromine abstraction from 2-BEMA. Depending on the concentrations of 2-BEMA and Mn2(CO)10 and irradiation time, hyperbranched polymers with different branching density and cross-linked polymers were formed. The resulting polymers possess unreacted bromide groups in the structure which allow postfunctionalization through visible light photopolymerization and Cu(I)-catalyzed click reactions.

Polyethylene-graft-poly(tert-butylacrylate) (PE-g-PtBA) copolymers were prepared by using a combination of ring-opening metathesis polymerization (ROMP), hydrobromination, and visible light-induced free radical polymerization. First, cis-cyclooctene was polymerized via ROMP in the presence of a chain transfer agent and quantitatively hydrobrominated. Poly(tert-butyl acrylate) (PtBA) chains were then grown via a grafting from approach from the Br-substituted linear poly(ethylene) (PE) backbone using dimanganese decacarbonyl (Mn2(CO)10) under visible light. The effect of Mn2(CO)10 concentration and irradiation time on the grafting density and efficiency was evaluated. The tert-butyl acrylate (tBA) esters of the graft copolymers were hydrolyzed into acrylic acid functionalities by acidolysis to obtain hydrophilic polyolefins. The precursor polymer, graft copolymer, and hydrolyzed polymer were characterized by 1H and 13C NMR, Fourier transform infrared, atomic force microscopy, and contact angle measurements.