Surface Modification of Sisal (Agavae sisalana) Fiber by Photocuring: Effect of Additives

The sisal fiber (Agavae sisalana) was grafted with methacrylonitrile (MAN) under UV radiation in order to modify its mechanical and degradable properties. A number of MAN solutions of different concentrations in methanol (MeOH) along with photoinitiator Darocur-2959 were prepared. The soaking time, radiation dose and monomer concentration were optimized. Sisal fiber soaked for 60 min in 50% MAN and irradiated at 8th UV pass achieved highest values of tensile properties like tensile strength (TS = 140.2 MPa), and elongation at break factor (Ef = 8) with 8% polymer loading (PL). To further improve the properties of sisal fiber, a number of additives (1%) such as urea (U), polyvinylpyrrolidone (PNVP), tripropelene glycol diacrylate (TPGDA), hexanediol diacrylate (HDDA), trimethyl propane triacrylate (TMPTA), ethylene glycol dimethacrylate (EGDMA) were used in the 50% MAN formulation to graft at the optimized condition. Among the additives used, urea has significantly influenced the PL (9%), TS (190 MPa), and Ef (9) values of the treated sisal fiber. Water uptake and accelerated weathering test were also performed.     

Comparison of mechanical and degradation properties of EG and EGDMA grafted gelatin films

Thin films of gelatin were prepared from gelatin granules in aqueous medium by casting and its mechanical properties like tensile strength (TS), tensile modulus (TM), and elongation at break (Eb %) were studied. Gelatin films were procured with two types of monomers such as 5% ethylene glycol (EG) and 5% ethylene glycol dimethacrylate (EGDMA) to increase the mechanical properties. Five percent of monomer solutions were prepared in MeOH along with 2% photoinitiator; Irgacure-651. Soaking time and UV radiation intensities were optimized with the extent of polymer loading (PL) and the mechanical properties of the cured films. Comparing the properties of EG and EGDMA treated gelatin film, EG showed the best performance. The EG-cured gelatin film with 5?min soaking time showed the highest tensile strength (58.6?MPa) and elongation at break (11.2%). The water uptake was determined for raw film (500.1%), EG grafted gelatin film (375.3%), and EGDMA grafted film (412.9%). The degradation properties in water and soil were determined for the raw and cured gelatin films. It was observed that the raw film degrades more than that of the treated films.     

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

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 (σ) of the pretreated fiber, were monitored. Fiber treated with 130th pass of radiation showed the higher TS, Eb, and σ. 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.     

Effect of pretreatment with detergent on mechanical properties of photocured coir (Cocos nucifera) fiber with ethyleneglycol dimethacrylate

Coir fibers were treated with ethylene glycol dimethacrylate (EGDMA) mixed with methanol (MeOH) under UV radiation. A series of solutions of different concentrations of EGDMA in methanol along with a photoinitator, Irgacure‐500 (mixture of 1‐hydroxylcyclohexylphenylketone and benzophenonc), were prepared. Monomer concentration, soaking time, and radiation intensity were optimized in terms of polymer loading (PL) and mechanical properties. EGDMA (50%), 5 min soaking time at the 4th pass of radiation, produced higher PL and tensile strength (TS), and the values of PL is 17% and TS is 1.3 times of the nontreated one. Then, coir fiber was pretreated with detergent and then treated with the optimized monomer formulation, which exhibited a higher PL of 69% and produced TS of the coir fiber of 4.4 times of the nontreated one. Coir fiber pretreated with detergent along with UV radiation showed the highest TS, which is 18.2 times of nontreated one. Water uptake, degradable properties, and simulated weathering of treated and virgin fibers were also monitored, which showed that EGDMA treatment under UV radiation improved the degradable property. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1630–1636, 2006     

Surface Modification of Jute Fabrics Using Acrylic Monomers: Effect of Additives

Jute fabrics were modified with methyl acrylate (MA), ethyl acrylate (EA), and 2-hydroxyethyl acrylate (2-HEA) using UV radiation at different periods of time. It was found that 30% MA at 60 min, 15% EA at 40 min, and 15% 2-HEA at 15 min irradiation time in methanol along with photoinitiator showed the best results. Some additives, such as urea, acrylamide (AM), ethylhexyl acrylate (EHA), tripropelene glycol diacrylate (TPGDA), and trimethylol propane triacrylate (TMPTA), were incorporated into the optimized monomer solutions and monitored its effect on the properties. Various physico-mechanical properties of both treated and untreated jute fabrics were also performed.     

Effect of alkali and ultraviolet (UV) radiation pretreatment on physical and mechanical properties of 1,6‐hexanediol diacrylate–grafted jute yarn by UV radiation

To improve the physicomechanical properties of jute yarn, grafting with 1,6‐hexanediol diacrylate (HDDA) monomer was performed by a UV radiation technique. A series of HDDA solutions of various concentrations in methanol were prepared. A small quantity of photoinitiator (Darocur‐1664) was also added to HDDA solutions. To optimize the conditions for grafting, the effects of monomer concentration, soaking time, and radiation doses were studied by varying the number of soaking times along with variation of monomer concentrations and UV radiation intensities. The extent of polymer loading and the mechanical properties like tensile strength (TS), elongation at break (Eb), and tensile modulus of both treated and untreated jute were investigated. The highest tensile strength, polymer loading, and modulus were achieved with 5% HDDA concentration, 5 min soaking time, and the 4th pass of UV radiation. This set of conditions was selected as optimum and produced enhanced tensile strength (67%), modulus (108%), and polymer loading (11%) over those of virgin fiber. To further improve the mechanical properties the jute yarns were pretreated with alkali (5% NaOH) solution and after that the alkali‐treated yarn were treated under UV radiation of various intensities. The pretreated samples were grafted with optimized monomer concentration (5% HDDA). Increased properties of alkali + UV‐pretreated and grafted samples such as polymer loading (12%), tensile strength (103%), elongation at break (46%), and modulus (114%) were achieved over those of virgin jute yarn. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 18–24, 2004     

Modification and characterization of photo-cured sodium alginate film with ethylene glycol: effect of additives

Thin films of sodium alginate (SA) were prepared by casting from methanol solutions. Tensile strength and elongation at break (Eb%) of the films were found to be 20.4 MPa and 11.6 %, respectively. A series of SA solutions (formulations) were prepared by blending varying percentages (2–8 % by wt) of ethylene glycol (EG) and then films were prepared and cured under UV radiation at different intensities (5–35 UV passes). Monomer concentration, soaking time, and radiation dose were optimized in terms of polymer loading and mechanical properties of the cured films. For the improvement of the properties, several acrylic monomers of different functionalities as additives (2 %) like 2-ethylhexyl acrylate, 1,4-butanediol diacrylate, and trimethylolpropane triacrylate were incorporated with EG with the aid of UV radiation. Further analyses of the prepared films were characterized by FTIR and thermogravimetric analysis. Water uptake behavior was determined for the raw and cured SA films.     

Role of Amino Acids on In Situ Photografting of Jute Yarn with Acrylamide Using Ultraviolet Radiation

Abstract

To improve the mechanical performance of jute yarn, grafting with acrylamide (AM) monomer has been performed on in situ UV radiation and optimized; the monomer concentration (30%) and irradiation time (60 min) attained 195% tensile strength with 22% polymer loading (PL). The effect of amino acids (1%) as additives in AM with photografted jute yarn at optimized system has been studied. The PL and tensile properties, such as tensile strength (TS) and elongation at break (Eb), of treated samples were enhanced by incorporation of amino acids, and the highest TS value (270%) and Eb value (300%) with 27% PL value were achieved by the sample treated with L‐arginine (Arg). Weak acid [3% acetic acid (Ace)] and strong acid [1% sulfuric acid (Sul)] were also incorporated in the optimized system of AM grafting to investigate their effect on the mechanical properties of photografted jute yarn. Water absorption and weathering resistance of treated untreated samples (TS₀) were also studied.     

Role of Urea on the Physico-Mechanical and Degradable Properties of Mercerized and Acid Hydrolyzed Coir (Cocos nucifera) Fibers Photocured with 1,6-Hexanediol Diacylate

Abstract

Coir fibers were modified with 1,6-hexanediol diacrylate (HDDA) by 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 the better performance registered as the optimum conditions, where polymer loading (PL) was 17% and tensile strength (TS) was 50%. Urea of different concentrations (0.5–2%) was incorporated with 30% HDDA to monitor its effect on the properties and 1% urea produced the enhanced PL (25%) and TS (82%). For the improvement of the properties, the fibers were subjected to surface treatment with alkali (5% potassium hydroxide) at various mercerizing times in hot and normal conditions. Among all the mercerized fibers, fibers treated with hot alkali for 6 h and cured under optimized condition demonstrated the maximum enhancement of PL (35.5%) and TS (130%). The fibers were also subjected to acid hydrolysis for different times with different acid (H₂SO₄) concentrations. Again the effect of urea (1%) on the properties of the pretreated fibers was scrutinized. Water uptake and degradable properties of the treated and virgin fibers were performed.     

Preparation and Characterization of the Mechanical Properties of the Photocured Chitosan/Starch Blend Film

The chitosan/starch blend films of 2:1 ratio were prepared by solution casting. Tensile strength (TS) and elongation at break (%Eb) of chitosan/starch blend film were found to be 9.33 MPa and 3.6%, respectively. The blend films (2% Chitosan) were soaked in six different formulations of methylmethacrylate (MMA) monomer and aliphatic urethane diacrylate oligomer (M-1200) at different time intervals (1–5 min) and irradiated under UV radiation at different intensities (5–35 pass). Formulations containing 43% MMA and 15% oligomer in methanol solution showed 209% increase in TS at 25th UV pass for 4 min soaking time. SEM and FTIR were used to investigate the molecular interaction and morphology of the blend film, respectively.     

A comparative study of gamma and ultraviolet radiation on gelatin film with 2-ethylhexyl acrylate

Gelatin films were prepared from gelatin granules in an aqueous medium by casting. Tensile strength (TS) and elongation at break (Eb%) of the films were found to be 29.2?MPa and 4.9%, respectively. Gelatin films were irradiated under gamma and UV radiation with different doses. Gamma treated gelatin films showed higher TS and Eb% over untreated ones, and even higher than that of the UV treated films. A series of gelatin solutions (formulations) was prepared by blending varying percentages (2–10% by wt) of 2-ethylhexyl acrylate (EHA) and then the films were prepared. Some EHA-blended gelatin films were irradiated under gamma radiation at various doses (50–500?krad) and other films were cured under UV radiation at different intensities (10–30 UV passes). EHA-blended?+?gamma treated gelatin films showed the highest mechanical properties than that of the EHA-blended?+?UV treated films. The degradation properties present in the soil were determined for the pure and treated films. It was observed that EHA-blended?+?gamma treated gelatin film degrades more than that of the EHA-blended?+?UV treated films.     

Effect of Radiation Pretreatment on Photo-grafting of Acrylamide on Cellulose

To study the photo-grafting performance of acrylamide (AM) onto cellulose and the mechanical behavior of grafted cellulose, Whatman 41 filter paper was grafted with 30% AM in methanol by UV radiation using in situ technique. The amount of grafting (Gf) and tensile properties like tensile strength (TS) and elongation at break (Eb) were studied. In order to improve the tensile properties, cellulose was pretreated under UV and gamma radiations at different radiation intensities and subjected to grafting with 30% AM under in situ UV radiation. Cellulose was also pretreated by alkali (5% NaOH) along with UV and gamma radiations with different intensities and grafted with AM under UV radiation. Among the treatments, the alkali + UV irradiated 30% AM grafted sample showed the best mechanical performance (TS = 200%, Eb = 250%).     

Mechanical properties study of photocured paperboard surface treated with aliphatic epoxy diacrylate

In order to improve the quality of paperboard (a well‐known packing material) surface by photocuring method, different formulations were developed with aliphatic epoxy diacrylate (EA‐1020) oligomer along with reactive monomers of various functionalities. The reactive monomers are tripropylene glycol diacrylate (TPGDA), a difunctional monomer, and trimethylol propane triacrylate (TMPTA), a trifunctional monomer. 2‐Benzyl‐2‐dimethylamino‐1(4morpholinophenyl) butanone‐1 (Irgacure 369), a photoinitiator (2%), was incorporated into the formulations to initiate photocuring reaction. The formulated solutions were coated on clean glass plate and irradiated under UV radiation of different intensities. Different physical properties like pendulum hardness and gel content of the cured films were studied. The formulation containing TMPTA showed better properties. After characterization of the films, these formulations were applied on paperboard surfaces and cured under the same UV radiation. Various physicomechanical properties such as pendulum hardness, tensile properties, surface gloss, adhesion, abrasion, and water uptake were studied. The best performance was obtained at 12 passes of radiation with 18% TMPTA‐containing formulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1774–1780, 2003     

Effect of Mercerization on Surface Modification of Henequen (Agave fourcroydes) Fiber by Photo-Curing with 2-Hydroxyethyl Methacrylate (HEMA)

Abstract

Henequen fibers were cured under ultraviolet (UV) radiation with 2-hydroxyethyl methacrylate (HEMA) in order to improve the mechanical properties and reduce the water absorption. A series of solutions of different HEMA concentration in methanol along with photoinitiator Irgacure 907 was prepared. The radiation dose, monomer (HEMA) concentration and soaking time were optimized with respect to grafting of monomer and mechanical properties of cured fiber. 3% HEMA, 5 min soaking time, at the ninth pass of radiation, produced higher tensile strength (190%) and elongation at break (195%), than those of the virgin fiber, as well as the highest grafting value (4.2%). For further improvement of the mechanical properties, the fibers were treated with an alkali (KOH) solution of various concentrations for 1 h before curing. 10% alkali-treated fibers showed increased properties, such as grafting (5.4%), tensile strength (300%), and elongation at break (290%) over raw fiber. The treated fiber showed lower water uptake than the untreated ones. The grafted fibers were also characterized by IR and it was observed that HEMA deposited on the fiber surface may react with the cellulose backbone of the Henequen fibers.     

Synthesis and characterization of palm‐based resin for UV coating

The production of UV curable acrylated polyol ester prepolymer from palm oil and its downstream products offer potential and promising materials for applications such as polymeric film preparation and coatings. In this study, palm olein polyol was reacted with acrylic acid in the presence of a catalyst and inhibitors via condensation esterification process. The reaction temperature of 80°C and the stirring rate of 400 rpm produce a homogeneous product. Based on iodine value result, the suitable amount of p‐toluene sulfonic acid monohydrate used as catalyst was 3.0% (w/w) of palm olein polyol. Different UV curable formulations have been investigated using the synthesized prepolymers with monomers and a small amount of photoinitiator. Monomers used were 1,6‐hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate (TMPTA) while photoinitiator used was 1‐hydroxy cyclohexyl phenylketone (Irgacure 184). The mixtures were cured to make thin polymeric films under UV radiation with doses between 2 and 14 passes (energy per pass is 0.6 J/cm²). Coating and curing was carried out on glass for pendulum hardness and FTIR analysis. Pendulum hardness of the film prepared using monomer HDDA and the prepolymer previously synthesized using 3.0% catalyst was 24.5%. The radiation dose needed was 14 passes. The highest pendulum hardness of 49.4% was achieved using monomer TMPTA and the prepolymer synthesized using 2.0% catalyst. The radiation dose needed was 10 passes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and evaluation of epoxy methacrylate UV‐curable coatings containing phthalazinone

Epoxy methacrylate resin (EMA) UV‐curable coatings exhibit high reactivity, low viscosity and excellent chemical resistance in environmentally friendly coatings. A novel EMA containing phthalazinone moieties for high temperature resistant UV‐curable coatings was synthesized. The formulations were cured with hexanediol diacrylate (HDDA) and trimethylol propane triacrylate (TMPTA) as reactive diluents promoted by a photoinitiator, and then interpenetrating polymer networks were generated. The mechanical, chemical and thermal properties of the clear coatings were characterized using Chinese National Standard methods (GB). EMA was used with UV radiation curing in combination with 6.7 wt% of HDDA and 13.4 wt% of TMPTA, and the properties of the cured films were as follows: pencil hardness of 5 H, 30% NaOH resistance for 30 days, 15% HCl resistance for 10 days, 3% NaCl resistance for 30 days and 5% weight loss temperature of 300.5 °C. EMA UV‐curable coatings containing phthalazinone exhibit excellent chemical and thermal stability, and could be potential candidates for UV‐curable zero volatile organic compound coatings applied in the fields of salt spray corrosion, strong radiation and high‐temperature resistance. Copyright © 2009 Society of Chemical Industry     

Effects of Surface Pretreatment on the Mechanical and Dielectric Properties of Photocuring Jute Fibers

Jute fabrics were treated with ethylene glycol dimethylacrylate (EGDMA) + MeOH solutions at different proportions along with photoinitiator Irgacure 907 and cured under UV-radiation. Monomer concentration, soaking time, and radiation dose were optimized in terms of polymer loading and mechanical properties. Twenty-five percent EGDMA, 30-minute soaking time, and tenth-pass of radiation produced higher tensile strength (75%) and tensile modulus (88%) than those of the untreated sample, as well as the highest polymer loading value (70%). Among different additives used, urea showed the best performance. SEM, water uptake, and dielectric properties of the samples were studied.     

Studies on the Mechanical Properties of Gelatin and Its Blends with Vinyltrimethoxysilane: Effect of Gamma Radiation

Gelatin films were prepared by casting. Tensile strength (TS), elongation at break (Eb) and tensile modulus (TM) of the gelatin films were found to be 56 MPa, 6.1% and 1.14 GPa, respectively. Effect of gamma radiation (Co-60) on the mechanical properties of the gelatin films was studied. Vinyltrimethoxysilane (VTMS) was added to the gelatin during casting varying 1–7% by weight and found to increase the TS and TM significantly. Then the films were irradiated and found further increase of TS and TM. Water uptake of the gelatin films and 5% VTMS containing gelatin films were also evaluated.     

Role of additives on UV curable coatings on wood

An epoxy resin-coating formulation was prepared from diacrylated epoxy bisphenol-A-epichlorohydrin and a reactive monomer, tripropyleneglycol diacrylate. The additives, silane and fluorochemicals, were included in the formulation to evaluate their effects on the UV curing of the epoxy resin onto timber. Thin films coated on wood substrates were cured under UV radiation in the presence of the photoinitiator, benzoin ethyl ether. Adhesion of the cured films onto wood substrates was evaluated using the cross-cut and the pull-off tests. Film hardness was evaluated using the pencil hardness and the pendulum hardness tests. Water repellency of the films were measured from contact angles using a telegoniometer. Scanning electron microscopy (SEM) was used to investigate the interface between the films and the wood substrates. These studies showed that silane only enhanced the adhesion of the film onto the wood substrates but had no effect on the hardness of the films. The additives improved the water repellency of the films with the fluorochemicals, exhibiting dramatic improvement. SEM revealed that only the fluorochemical aided the penetration of the resin into the wood. © 1996 John Wiley & Sons, Inc.     

A comparative study on the mechanical and degradation properties of plant fibers reinforced polyethylene composites

Coir and abaca fiber‐reinforced linear low density polyethylene (LLDPE) composites (30 wt% fiber) were prepared by compression molding. Coir and abaca fibers were treated with methyl methacrylate (MMA) using ultraviolet radiation to improve the mechanical properties of the composites. Concentration of MMA and radiation dose was optimized. It was found that 30% MMA in methanol along with photoinitiator Darocur‐1173 (2%) and 15th pass of radiation rendered better performance. Chemically treated fiber‐reinforced specimens yielded better mechanical properties compared to the untreated composites, whereas coir fiber composites had better mechanical properties than abaca fiber reinforced ones. For the improvement of the properties, optimized coir (coir fiber treated with 30% MMA) and abaca (abaca fiber treated with 40% MMA) fibers were again treated with aqueous starch solution (2%–8%, w/w) for 2–7 min. Composites made of 3%‐starch‐treated coir fiber (5 min soaking time) showed the best mechanical properties than that of abaca‐fiber‐based composites. Water uptake and soil degradation tests of the composites were also performed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers