Machine Learning Approach for Prediction of the Grafting Yield in Radiation-Induced Graft Polymerization

Grafting yields for the radiation-induced graft polymerization of a methacrylate ester monomer to give a polyethylene-coated polypropylene nonwoven fabric were predicted as an objective variable by a machine learning approach. The degrees of grafting were obtained from actual experiments. Monomer structure information, atomic charge information, atomic NMR shift information, and infrared absorption wavenumber information, derived from density functional theory calculations, were adopted as explanatory variables of a grafting yield prediction model. Among machine learning algorithms as a prediction model on the grafting yield, XGBoost and random forest models showed higher prediction accuracy, compared to a multiple linear regression model. The prediction accuracies of the various algorithm decreased in the order: XGBoost > random forest > multiple linear regression/LASSO > decision tree > multiple linear regression. The monomer polarizability and the O2 NMR shift were found to be important explanatory variables for predicting the grafting yield in the XGBoost model. This is probably because the polarizability, which represents a miscibility indicator of the monomer to the trunk polymer, and the O2 NMR shift, which represents a diffusivity indicator of the monomer into the trunk polymer, remarkably reflect the difference in the substituent structure of the methacrylate ester monomers

Development of Radiation-Grafted Fibrous Adsorbents for Trivalent and Hexavalent Chromium Removal

To remove toxic chromium ions from aqueous solution, pendant amino/amido ligand adsorbents onto a fine polyethylene fabric with a nonwoven form were synthesized by electron beam induced graft polymerization of 4-Chloromethylstylene/acrylonitrile monomer and subsequent chemical modification. The ligand density of the obtained grafted adsorbents ranged from 3.6 to 4.2 mmol/g- adsorbent. In batch adsorption tests, the amine- and amide-type adsorbents were performed in trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) solution having a concentration of 100 ppb in the pH range from 2 to 7. As a result, the resultant amine-type adsorbent had higher affinity for Cr(IV) at pH 3-5, and amido-type’s had for Cr(III) at pH 5-7. Almost all adsorbed Cr on the grafted adsorbent could be eluted in acidic solution, and the adsorbent can be used repeatedly after the elution of Cr. Column mode adsorption tests indicated that the adsorption rate of the obtained fibrous adsorbents had much higher than that of general granular shaped resin

Bleed-out suppression of silicone rubber by electron beam crosslinking

A silicone rubber with a highly crosslinked surface layer was synthesized by a two-step crosslinking reaction with thermal processing and subsequent electron beam (EB) irradiation. The effect of the EB irradiation on the silicone rubber was evaluated by measuring the volume swelling ratio, shore hardness, tensile breaking strength, and water contact angle of the EB-crosslinked silicone rubber. The silicone rubber was effectively crosslinked as the EB irradiation increased. The optimal EB irradiation dose to form the EB-crosslinked structure in the silicone rubber was 500 kGy. Insufficient EB irradiation does not form a sufficient EB-crosslinked structure, while excessive EB irradiation dose would decompose the silicone rubber. The finer crosslinked structures of the surface layer of the silicone rubber formed by EB irradiation could function as a leak-proof filter to prevent the bleed-out of low-molecular-weight siloxanes inside the silicone rubber. The effect of the type of EB-crosslinking agent on the bleed-out suppression effect was investigated. The bleed-out suppression effect was improved in the following order: no EB-crosslinking agent < ethylene glycol dimethacrylate < silicone diacrylate < trimethylolpropane trimethacrylate (TMPTMA). The thermally and EB-crosslinked silicone rubber with TMPTMA successfully reduced the bleed-out ratio by approximately 60%, compared to the thermally crosslinked silicone rubber without EB irradiation and EB crosslinking agent

Development of a Simplified Radiation-Induced Emulsion Graft Polymerization Method and Its Application to the Fabrication of a Heavy Metal Adsorbent

A simplified radiation-induced emulsion graft polymerization (SREG) method is proposed. This method involves a convenient and easy degassing process of a monomer solution using a commercially available sealed glass jar. A loaded weight on the lid of the jar was used to control the jar’s internal pressure as the degassing of the monomer solution took place using a vacuum pump. The degassing method was highly reproducible, resulting from no bumping of the monomer solution. The initial grafting velocity was proportional to the absorbed doses of pre-irradiation between 5 and 20 kGy. This result indicates that dissolved oxygen was sufficiently eliminated from the monomer solution at such a level where the remaining oxygen had little effect on the grafting reaction at a dose of 5 kGy. The method was then applied to the fabrication of a heavy metal adsorbent that possessed a sufficient adsorption capacity of Co(II) ions. The SREG method is applicable to the fabrication of a wide variety of functional graft polymers because high-dose-rate gamma-ray radiation and expensive experimental equipment are not necessary

Surface Engineering of Fluoropolymer Films via the Attachment of Crown Ether Derivatives Based on the Combination of Radiation-Induced Graft Polymerization and the Kabachnik–Fields Reaction

In this manuscript, we present the successful attachment of crown ether moieties onto fluoropolymer surfaces, via the combination of radiation-induced graft polymerization and a subsequent surface Kabachnik–Fields three-component reaction. The obtained crown ether-tethered fluoropolymer films exhibited an ammonium cation capturing ability, owing to the host–guest interactions (i.e., hydrogen bonding) between the surface-anchored crown ethers and the guest ammonium cations

Palm oil-based biodiesel synthesis by radiation-induced kenaf catalyst packed in a continuous flow system

An efficient bio-based heterogeneous catalyst for biodiesel production was successfully fabricated by radiation-induced graft polymerization of 4-vinylbenzylchloride (VBC) followed by quaternary amination of trimethylamine (TMA) and ion-exchange with aqueous sodium hydroxide onto kenaf bast fiber using electron beam irradiation at a dose of 150 kGy. The produced catalyst was characterized by FESEM–EDX, CHNS, ATR-FTIR, TGA and XRD analyses. In this study, the continuous catalytic transesterification of triolein/ethanol in a bench-scale packed bed reactor (PBR) was designed and tested. The reaction process was focused at room temperature, different residence times from 1 min to 4 min and a molar ratio of triolein/ethanol (1:50). Besides, study on the transesterification of palm oil with ethanol under optimized conditions for maximum conversion of triolein to ethyl oleate (residence time of 3 min, LHSV = 8 h^−1, short chain 150kGy catalyst) with temperature fixed at room temperature (˜25 °C) has been carried out. The extracted ethyl oleate was analyzed by HPLC and ATR-FTIR. The results found that the continuous flow system has a great potential for producing ethyl ester to be used as biodiesel and it is possible to generate 100% biodiesel with high purity from palm oil using radiation-induced kenaf catalyst