Radiation-induced reactions with cellulose. IX. Copolymerization with styrene using a pre-irradiation procedure and the effect of additives on the grafting reaction

J of Applied Polymer Sci

Hassan

Taslima

et al. 2006

ABSTRACT:Coir fibers were modified with 1,6-hexanediol diacrylate (HDDA) using ultraviolet (UV) radiation. Concentration of HDDA, soaking time, and radiation dose were optimized and found to be 30% HDDA in methanol along with photoinitiator Irgacure-500 (2%) and 120 min of soaking time registered as the better performance (polymer loading (PL) 7%, tensile strength factor, T f ϭ 1.50). Urea of different concentrations (0.5-2%) were incorporated with 30% HDDA to monitor its effect on the properties and 1% urea produced the best results (PL ϭ 25%, T f ϭ 1.82). For the improvement of the properties, the fibers were subjected to surface treatment with potassium permanganate (KMnO 4 ) of different concentrations at various treating times. Enhanced properties (PL ϭ 86%. T f ϭ 4.42) of the fibers treated with KMnO 4 (0.05%) were obtained. The KMnO 4 treated fibers were again treated with HDDA (30%) solution along with urea (1%) and found to produce the best results (PL ϭ 100%, T f ϭ 4.5). Water uptake and degradable properties of the treated and virgin fibers were obtained.

Section: Polymer Loadingmentioning

confidence: 98%

Role of pretreatment with potassium permanganate and urea on mechanical and degradable properties of photocured coir (Cocos nucifera) fiber with 1,6‐hexanediol diacrylate

J of Applied Polymer Sci

Hassan

Taslima

et al. 2006

“…The highest grafting value (4.5 %) is observed for 6 min soaking time followed by 10 min soaking time. The diffusion of monomer into the fiber, the swelling of trunk polymer, and the Trommsdrof effect of solvent on graft polymer radicals [21] affect the radiation induced graft copolymerization reaction of vinyl monomer onto the cellulose backbone. Swelling of the fibers on the bulk monomer increases the cross-section of the fiber at the same time the fiber surface becomes lustered.…”

Section: Optimization Of Soaking Time In Monomer Methanol Solutionmentioning

confidence: 99%

Effect of chemical modifications on the performance of biodegradable photocured coir fiber

Zaman

et al. 2011

Fibers Polym

Coir fibers (Cocos nucifera) were treated with 1-ethyl-2-pyrrolidone (1-E-2-P) mixed with methanol (MeOH) under UV radiation. A series of solutions of different concentrations of 1-E-2-P in methanol along with a photoinitiator, Darocur-1173, were prepared. Monomer concentration, soaking time, and radiation dose were optimized in terms of grafting and mechanical properties. Ten percent 1-E-2-P, 6 min soaking time, and a 15th pass of radiation produced higher tensile strength (53 %) and elongation at break (230 %) than those of virgin fiber, as well as the highest grafting value (4.9 %). The effect of additives (1 %), such as urea and silane (3-trimethoxysilyl propyl methacrylate) on the properties of coir fiber was studied. Among the additives used, silane showed the best performance. For further improvement of the properties, the fibers were treated with alkali (potassium hydroxide) solution of different temperatures (0-60 o C). A 10 % alkali-treated fiber showed the best properties such as grafting (6.2 %), tensile strength (72 %) and elongation at break (330 %) over virgin fiber. The silane-treated fiber produced the minimum loss of the properties, as well as a lower water uptake than those of the untreated one. The effect of simulating weathering on the degradation properties of samples was also performed.

“…It is observed from the figure that PL values increase with soaking time up to 7 min, and after 7 min, the values decrease with increasing soaking time. The photocuring reaction of monomer onto cellulose backbone is effected by the diffusion of monomer into the fiber, the swelling of trunk polymer, and the Trommsdorff effect of solvent on cured polymer radicals [30,31] . Swelling increases the cross-sectional area of the fiber.…”

Section: Optimization Of Soaking Time and Radiation Dosesmentioning

confidence: 99%

Effect of Pretreatment with Ultraviolet Radiation on the Physicomechanical Properties of Photocured Coir (Cocos nucifera) Fiber with 1-Ethyl-2-Pyrrolidone (1-E-2-P) Monomer

Polymer-Plastics Technology and Engineering

Bhattacharia

Ahmed

et al. 2006

Coir fiber (Cocos nucifera) was modified with 1-ethyl-2-pyrrolidone (1-E-2-P) monomer by photocuring. A series of formulations of different concentration of 1-ethyl-2-pyrrolidone (3, 5, 10, 20, 30, and 70%) in methanol was prepared along with 2% photoinitiator (Darocur-1664). Concentration of 1-E-2-P, soaking time, and radiation doses were optimized and found that 5% 1-E-2-P, 7 min soaking time, and 5th pass of UV radiation was the optimized condition that gave the maximum values as polymer loading (PL) (21%) and 71% higher tensile strength over virgin one. The coir fiber was pretreated with ultraviolet (UV) radiation of various intensities for further improvement of mechanical properties. The mechanical properties, such as TS (tensile strength), Eb (elongation at break), and modulus (r) of the pretreated fiber, were monitored. Fiber treated with 130th pass of radiation showed the higher TS, Eb, and r. The fiber irradiated at 130th pass of UV radiation gave the maximum values as PL (35%) and 74% and 18% higher tensile strength and elongation at break, respectively. The fiber, both treated and untreated, was subjected to water absorption. The pretreated and cured coir fiber showed the minimum water uptake behavior.