Facile Molecular Weight Determination of Polymer Brushes Grafted from One-Dimensional Diffraction Grating by SI-ATRP Using Reflective Laser System

Gelatin was immobilized selectively on the amide groups-modified bottom of a trench array of a photoresist template with 2 μm resolution by the ethyl(dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide reaction. The gelatin-immobilized line array was brominated to generate a macroinitiator for atom transfer radical polymerization. Poly(methacrylic acid) (PMAA) brushes were grafted from the macroinitiator layer as line arrays of one-dimensional diffraction gratings (DGs) for various grafting polymerization times. A laser beam system was employed to analyze the optical feature with a characteristic diffraction effect of the PMAA DGs at a 45° incident angle along the transverse magnetic and transverse electric polarization. The growth of the PMAA brush lines increased both their heights and widths, leading to a change in the reflective diffraction intensity. The PMAA brushes under various grafting polymerization times were cleaved from the substrate by digestion of gelatin with trypsin, and their molecular weights were obtained by gel permeation chromatography. The change degree of the diffraction intensity varied linearly with the molecular weight of the PMAA brushes over a wide range, from 135 to 1475 kDa, with high correlation coefficients. Molecular weight determination of polymer brushes using the reflective diffraction intensity provides a simple method to monitor their growth in real time without polymer brush cleavage.

Comparative Study on Different Modified Preparation Methods of Cellulose Nanocrystalline

Different modification process routes are used to improve the modified cellulose nanocrystalline (MCNC) with higher fatty acid by esterification reaction and graft polymerization to obtain certain hydrophobic properties. Two preparation methods, product structure and surface activity, are compared and explored. Experimental results show that the modified product is still at the nanometer level and basically retains the crystal structure of the raw cellulose nanocrystalline (CNC). The energy consumption of the two preparation methods is low; however, the esterification method with co-reactant requires short reaction time, and the degree of substitution of the product is high. The modified product prepared by grafting polymerization method has a high HLB value and amphiphilicity, which can effectively reduce the surface tension of water. Therefore, it can be used as a green and environmentally friendly surface-active substance.

Synthesis and characterization of polypropylene glycol-graft-styrene

Grafting polymerization based on polypropylene glycol (PPG) and styrene (St) was synthesized with different composition of styrene using the free radical technique in the presence of potassium persulphate as an initiator. The grafted copolymers (PPG-g-St) used different styrene composition (65/15, 65/25, 65/35), respectively. The grafted copolymers were investigated through FTIR (Fourier-transform spectroscopy), Differential scanning calorimeter and thermogravimetric analyzer. FTIR showed new peaks at 1450 cm-1 and 1135 cm-1 due to the grafting process of St on PPG. Thermal stability of grafted copolymer increases by increasing the ratio of styrene, while Tg decreases by increasing the ratio of styrene.

Modification of Natural Leather Properties via Grafting Polymerization of Glycidyl Methacrylate Monomer

The authors have requested that this preprint be withdrawn due to erroneous posting.

Modification of Natural Leather Properties via Grafting Polymerization of Glycidyl Methacrylate Monomer

Chrome tanned leather was grafted by poly (glycidyl methacrylate) (L-g-PGMA) via emulsion polymerization technique and the grafting yield 26%. Epoxy content of the grafted leather samples was 69.4 mmol/100gm. The obtained L-g-PGMA samples were impregnated in different dibutyl amine solutions using amine/ epoxy molar ratio ranging from 0.5 up to 2.5. The obtained samples were assessed through varying nitrogen analysis, infrared spectroscopy, thermogravemetric analysis (TGA) analysis and scanning electron microscope. It was found that the nitrogen content of the treated leather samples increases by increasing the dibutyl amine concentration up to amine/ epoxy molar ratio of 2 after which it decreases. The water absorption, tensile strength and elongation (%) as well as hardness of the modified leather samples were studied and compared with the unmodified one. The colour strength values of dyed leather samples with acid dye were found to increase by grafting or by increasing the amine/epoxy molar ratio up to a value of 1.0 after which it decreases. On the contrary, the colour strength value of dyed leather sample with reactive dye sharply decreases after grafting with poly (glycidyl methacrylate). Samples grafted with glycidyl methacrylate and treated with dibutylacrylate amine exhibit increased colour strength which is directly related to the nitrogen content of the sample.

Visible light-induced controlled surface grafting polymerization of hydroxyethyl methacrylate from isopropylthioxanthone semipinacol-terminated organic monolayers

Reaction scheme of the visible light-induced controlled surface grafting polymerization of methacrylate monomers onto organosilane-coated silicon initiated by previously coupled dormant ITXSP groups.