Pattarapan Prasassarakich

Chulalongkorn University · Department of Chemical Technology

This work aimed to study the deoxygenation of two different waste cooking oils (WCOs; palm oil and soybean oil) using alumina (γ-Al2O3)-supported and unsupported NiMoS2 catalysts prepared by the hydrothermal method. The variables evaluated in this study were the reactant concentration, reaction time, and nickel (Ni)/[Ni + molybdenum (Mo)] atomic ra...

Protective packaging, such as loose-fill material, is commonly used for void filling in packages during transportation and handling. Due to environment concerns about packaging materials, alternative materials derived from agricultural residues, such as corn stalks (CS), are of attention. Dried internodal CS without rind (DCS-R) were prepared as a...

Natural rubber (NR) vulcanizates with waste zinc oxide (ZnO) particles were prepared through a sulfur vulcanization process. This research aimed to investigate the effect of different ZnO sources as an activator: commercial ZnO (ZO), waste ZnO obtained from a ceramic industry (WZO), and calcinated WZO (C-WZO) on the properties of NR vulcanizates. T...

Poly(methyl methacrylate)-silica (PMMA-RAFT-SiO2) nanocomposite emulsion was successfully synthesized via a combination of differential microemulsion polymerization (DMP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization. The PMMA-RAFT-SiO2 emulsion with a low SiO2 loading (10 wt%) exhibited nano-sized particles (49 nm) wit...

In this study, modified natural rubber (MNR) was used as a solid adsorbent for carbon dioxide (CO2) capture. The chemical structure of the NR latex was modified by diallylamine. Moreover, the silica particles were modified by (3-aminopropyl)trimethoxysilane, N-[(3-trimethoxysilyl)propyl]ethylenediamine, or N-[(3-trimethoxysilyl)propyl]diethylenetri...

Research on the production of bio-hydrogenated diesel as a green second-generation biodiesel is increasingly attractive for renewable energy utilization in engines, and has potentially been produced from the hydrotreating of vegetable oils. The present work investigated the hydrodeoxygenation of palm oil catalyzed by unsupported nickel-molybdenum (...

Poly(methyl methacrylate) (PMMA)-graphene emulsion was prepared via reversible addition-fragmentation chain-transfer (RAFT) polymerization using a hydrophilic macro-RAFT agent. In addition, the graphene was prepared using waste graphite from a metal smelting industry to reduce the cost of polymer composites and be more eco-friendly. The graphene ox...

The presence of aromatics and nitrogen compounds in petroleum fuel has a strong inhibiting impact on deep adsorptive desulfurization (ADS). This work aimed to clarify the individual and simultaneous effect of these compounds on ADS of the most refractory sulfur-containing polyaromatic compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene) ov...

A single-stage synthesis of isoprene from methyl tert-butyl ether (MTBE) and formalin in an organic-aqueous two-phase system was studied by using solid acid catalysts, i.e., USY zeolite, silicotungstic acid (STA) 25 wt% encapsulated in MIL-101(Cr) (STA25@MIL-101), and STA 25 wt% encapsulated in SBA-15 (STA25@SBA-15). From preliminary experiments, t...

Second generation biodiesel, so-called bio-hydrogenated diesel (BHD), can be produced from hydrotreatment of vegetable oils. The hydrogenation (HDO) of oleic acid and palmitic acid as model compounds of palm oil over unsupported Ni-Mo and Co-Mo sulfide catalysts was performed in a Parr reactor to produce BHD. The effects of reaction parameters: tem...

Oil palm shell (OPS) was converted to bio-oil in supercritical ethanol–water via one- and two-stage liquefaction. In the 1st stage, the OPS liquefaction was performed using 5 or 10% by weight (wt%) NaOH or KOH as the catalyst at 330 °C and an initial hydrogen (H2) pressure of 4 MPa. In the 2nd stage, the solid residue (SR) from 1st stage was again...

Developing selective and active catalyst is critical for CO2 hydrogenation to higher hydrocarbons especially C5+ products. The present work reports on the significant promoting effects of K and La addition to Fe–Cu/TiO2 catalyst on higher hydrocarbon production from CO2 hydrogenation. The incorporation of both K and La promoters can improve both CO...

A comparative study was carried out on the CO2 hydrogenation activities and product selectivities of the titania-supported monometallic and bimetallic Fe-based catalysts prepared by one-step wet impregnation. Among the monometallic catalysts (Fe, Co and Cu/TiO2), only Fe/TiO2 catalyst exhibited some selectivity to higher hydrocarbons, while Co/TiO2...

Polyisoprene-silica (PIP-co-RAFT-SiO2) nanoparticles were prepared via reversible addition–fragmentation chain-transfer (RAFT) emulsifier-free emulsion polymerization using water-soluble initiators, 4,4′-Azobis (4-cyanopentanoic acid) (ACP) and 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (V50). The particle size of emulsion prepared using...

A single-stage synthesis of isoprene from methyl tertiary-butyl ether (MTBE) and formalin in an organic-aqueous two-phase system were studied by using Cs-exchanged silicotungstic acid catalysts (CsXH4-XSiW12O40, abbreviated as CsX-STA). The CsX-STA catalysts (x = 2.0, 2.5, 3.0, and 3.5) were prepared using Cs2CO3 as Cs source and water as solvent....

Poly(methy methacrylate) (PMMA)-SiO2 nanoparticles were prepared via differential microemulsion polymerization. The effects of silica loading, surfactant concentration, and initiator concentration on monomer conversion, particle size, particle size distribution, grafting efficiency, and silica encapsulation efficiency were investigated. A high mono...

A series of linear low-density polyethylene films were produced using a three-layer co-extrusion machine. How the blow-up ratio and resin characteristics affected the final film morphology and engineering properties were studied. The crystalline morphology and orientation during the blown film process of the low-density polyethylene film were inves...

Self-healing hybrid nanocomposite was successfully prepared from epoxy resin containing self-healing microcapsules and organosilane modified nanosilica to enhance the anticorrosion performance of an epoxy coating. Nanosilica surface was modified with (3-glycidoxypropyl)trimethoxysilane (GPTMS) and (3-aminopropyl)trimethoxysilane (APTES) to accompli...

Low cost fumed silica (fSi) modified by polyethyleneimine (MW of 800) at 40 wt.% (fSi-PEI800-40) appears to be a promising sorbent for the binary sorption of CO2 and H2S. This study aimed to pelletize this powder sorbent using an extrusion method with starch, polyvinyl alcohol (PVA) or bentonite clay as a binder. The effect of the amount and type o...

A liquid-phase single-stage synthesis of isoprene from methyl tertiary-butyl ether (MTBE) and formalin using Keggin-type heteropolyacids, phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and silicotungstic acid (STA) was performed in a batch reactor. The effects of catalyst concentration, reaction temperature, MTBE/formaldehyde ratio and solv...

Polystyrene-silica (PS-co-RAFT-SiO2) nanoparticles were synthesized via reversible addition-fragmentation chain-transfer (RAFT) emulsifier-free emulsion polymerization using poly (styrenesulfonate-sodium.)-RAFT agent (macro-RAFT agent). The effects of macro-RAFT agent to initiator ratio on monomer conversion, particle size, particle size distributi...

The modification of silica particles with phenyltrimethoxysilane or N-[3-(trimethoxysilyl)propyl]aniline via a sol–gel reaction was performed in order to improve the dispersion of silica and antidegradation in natural rubber (NR). The functional groups on the modified silica surface were characterized by Fourier transform infrared spectroscopy, whi...

This work sought to improve the toughness and thermal stability of poly(lactic acid) (PLA) by incorporating poly(butylene succinate) (PBS) and wood flour (WF). The PLA/PBS blends showed a PBS-dose-dependent increase in the impact strength, elongation at break, degree of crystallinity, and thermal stability compared to the PLA, but the tensile stren...

Low cost fumed silica modified by amine addition with the ability to remove both carbon dioxide (CO2) and hydrogen sulfide (H2S) was developed. The effect of amine type (polyethyleneimine with a molecular weight of 800 (PEI800), aminoethylethanolamine, N-(3-trimethoxysilypropyl) diethylenetriamine, diethylenetriamine, triethylenetetramine and tetra...

The aim of this research was to investigate the important effects and their interaction on production of Green High Impact Polystyrene (HIPS) synthesized by using natural rubber (NR) as elastomeric phase via suspension polymerization initiated and stabilized by using benzoyl peroxide (BPO) and poly(vinyl alcohol) (PVA), respectively. The effects of...

The modification of silica surface by phenyltriethoxysilane (PhTES) as a modifying agent was carried out by sol-gel reaction of tetraethoxysilane (TEOS) as a precursor of silica. The condition to modify silica particles was the use of the mole ratio of TEOS to PhTES of 1:0.4 and ammonia as a catalyst at ambient temperature for 24 h. The characteriz...

Waste tires are attractive sources for alternative energy due to their long hydrocarbon chains with a high heating value. However, the condensed (volatile portion) pyrolysis oil derived from waste tires contains a relatively large level of sulfur compounds (1.15 wt%), which is not appropriate for use in combustion engines. Therefore, this research...

The efficiency of modified silica (SiO2) particles in the reinforcement of natural rubber (NR) vulcanizates was evaluated. The SiO2 particles were synthesized via a sol gel reaction using tetraethyl orthosilicate as the precursor, and then the formed SiO2 particles were modified with methyl, vinyl or aminopropyl groups using methyltriethoxysilane,...

High porosity and adsorbent silica xerogels modified by the addition of amine groups, triamine (TRI) or polyethyleneimine (PEI), were developed for the low temperature removal of H2S from biogas. The H2S adsorption and desorption abilities were characterized in a fixed-bed system with respect to the effect of the amine type, loading amount, operati...

Neodymium (Nd)-based Ziegler–Natta catalyst has been well known for preparing polybutadiene rubber (BR) containing high, about 98%, cis−1,4 configuration with extremely low gel content providing superior resistance to low-temperature fatigue and abrasion. However, its cost is more expensive than a conventional nickel (Ni)-based catalyst. The Nd-BR...

The undesirable properties of natural rubber (NR) can be improved via hydrogenation and graft copolymerization. Hydrogenated NR (HNR) latex was prepared via diimide reduction and then grafted with styrene (ST) or ST/methyl methacrylate (MMA) to form poly(ST)-graft-HNR (poly(ST)-g-HNR, GHNRS) or poly(ST-co-MMA)-g-HNR (GHNRSM), respectively. For the...

The use of naturally renewable shells of the freshwater channeled applesnail, Pomacea canaliculata, as a filler to replace commercial calcium carbonate (CaCO3) was investigated in this study. Ground P. canaliculata shell particles were converted to nano-CaCO3 particles by the displacement reaction of calcium chloride in sodium carbonate solution fo...

Hydrogenated polyisoprene (HPIP) nanoparticles, synthesized via organic solvent-free hydrogenation using RhCl3/TPPMS as catalyst, are novel nanofillers for natural rubber (NR) blends. Hydrogenation of a polyisoprene (PIP) emulsion was carried out in a Parr reactor. Rhodium trichloride (RhCl3.3H2O) and monosulfonated triphenylphosphine (TPPMS) were...

Polyaniline/montmorillonite (PANI/Mt) nanocomposites (1–7% (w/w) Mt based on the aniline content) were synthesized by in situ chemical oxidative polymerization with a 73.4–75.8% monomer conversion level. Fourier-transform infrared and scanning electron microscopy analyses confirmed the presence of Mt incorporation into PANI, whilst X-ray diffractio...

Natural rubber (NR) composites reinforced by silica generated in situ within the NR matrix were prepared by the sol–gel process using tetraethoxysilane (TEOS) as the silica precursor. The effect of the TEOS content, water: TEOS mole ratio, reaction time and temperature on the in situ silica content formed in the NR latex were investigated. The resu...

The filling of styrene graft natural rubber (ST-GNR) with in situ formed silica was performed using the sol–gel reaction via the latex solution method. The mechanical properties of ST-GNR/NR vulcanizate were improved when using the in situ formed silica to levels higher than those obtained with the commercial ex situ formed silica filled ST-GNR/NR...

Polyisoprene–montmorillonite (PIP–Mt) nanocomposites with an average particle size of 30 ± 7.2 nm and narrow size distribution (20–50 nm) were successfully synthesized via differential microemulsion polymerization. X-ray diffractometry analysis revealed that PIP was intercalated in the Mt layers expanding the d spacing of the Mt layer from 3.1 nm t...

Among Ziegler-Natta catalysts used for 1,3-butadiene (1,3-BD) polymerization, the advantage of a neodymium (Nd)-based catalyst is that it provides butadiene rubber (BR) with a high content of cis-1,4 configuration and a low amount of vinyl-1,2 units. Whereas, a cobalt (Co)-based catalyst can produce BR with a low content of trans-1,4 configuration....

This paper reports on Fe–Co bimetallic catalysts that are active and selective for synthesis of olefin-rich C2+ hydrocarbons from CO2 hydrogenation. The combination of Fe and a small amount of Co led to a dramatic bimetallic promotion of C2+ hydrocarbons synthesis in CO2 hydrogenation on Fe–Co/Al2O3 catalyst with 15 wt% total metal loading. The add...

Rhodium catalysts are effective catalysts for catalytic hydrogenation of unsaturated polymers in aqueous media under optimum conditions. Hydrogenation of a nanosized polyisoprene (PIP) emulsion was carried out in a Parr reactor. Rhodium trichloride (RhCl3 center dot 3H(2)O) and different ligand types, triphenylphosphine (PPh3), trisulfonated triphe...

Natural rubber (NR) latex was grafted by emulsion polymerization with styrene monomer, using cumene hydroperoxide/tetraethylene pentamene as redox initiator system. The polystyrene-grafted NR (PS-g-NR) was hydrogenated by diimide reduction in the latex form using hydrazine and hydrogen peroxide with boric acid as a promoter. At the optimum conditio...

A water-soluble rhodium catalyst has been found to be an efficient catalyst for hydrogenation of unsaturated polymers in the absence of any organic solvent. Natural rubber (NR) latex and synthetic polyisoprene (PIP) emulsion were hydrogenated using rhodium trichloride (RhCl3·3H2O) and different ligand types, triphenylphosphine (PPh3), trisulfonated...

The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated...

Hydrogenated polyisoprene (HPIP)-SiO2 nanocomposites were synthesized via differential microemulsiion polymerization followed by diimide hydrogenation. First, the isoprene monomer was polymerized on the silane treated nanosilica by differential microemulsion polymerization to obtain polyisoprene (PIP)-SiO2 nanoparticles with a particle size of 43 n...

This paper reports on notable promotion of C2 + hydrocarbons formation from CO2 hydrogenation induced by combining Fe and a small amount of selected transition metals. Al2O3-supported bimetallic Fe–M (M = Co, Ni, Cu, Pd) catalysts as well as the corresponding monometallic catalysts were prepared, and examined for CO2 hydrogenation at 573 K and 1.1...

Nanosized ethylene–propylene rubber (EPM) latex with a particle size of 47 nm was synthesized via an alternative route consisting of isoprene (IP) polymerization followed by hydrogenation. First, the IP monomer was polymerized by differential microemulsion polymerization to obtain polyisoprene (PIP) rubber latex with a particle size of 42 nm. The s...

The graft copolymerization of styrene onto nanosized polyisoprene (PIP) was carried out by using cumene hydroperoxide and tetraethylene pentamine as redox initiators. The high conversion and high degree of grafting could be achieved when a small particle was used as the core polymer. The grafting efficiency and monomer conversion increased with inc...

The structural properties and catalytic functionality of two different morphologies of unsupported MoS2 catalysts were investigated systematically. Hydrodeoxygenation (HDO) of phenol was used as the model reaction to examine the effect of the catalyst structure on the hydrogenolysis and hydrogenation activity and selectivity. The unsupported MoS2,...

Monodispersed polyisoprene–SiO2 nanoparticles were successfully synthesized by a differential microemulsion polymerization of isoprene on silane treated nanosilica. Core–shell morphology was formed consisting of silica as the nano-core encapsulated by polyisoprene (PIP) as the nano-shell, as confirmed by TEM. PIP–SiO2 nanoparticles were produced at...

Depolymerization of cellulose is a significant part of the challenge in converting lignocellulosic biomass to valuable products such as monomeric sugars. Aiming to develop a new approach for efficient depolymerization of cellulose, we explored a sequential combination of organic acid (oxalic acid, OA) and base (tetramethylammonium hydroxide, TMAH)....

Unsupported sulfide catalysts are a potentially promising approach towards furthering the understanding and development of a better heterogeneous catalytic system capable of performing the hydrodeoxygenation (HDO) of bio-oil proficiently under mild and short reaction conditions and times, respectively. Amorphous unsupported Ni–Mo sulfide, prepared...

A graft copolymer of acrylonitrile (ACN) and styrene (ST) on natural rubber (NR) was prepared by solution polymerization initiated by benzoyl peroxide. The effect of graft NR (GNR) applied as a compatibilizer for NR/nitrile rubber (NBR) blends on their mechanical and physical properties was investigated. The results revealed that the tensile proper...

In situ silica reinforcement of natural rubber (NR) grafted with methyl methacrylate (MMA) (MMA-GNR) was achieved via the sol–gel reaction of tetraethoxysilane (TEOS) by the use of solid rubber and latex solutions. Silica contents within the MMA-GNR as high as 48 and 19 phr were obtained when using the solid rubber and latex solutions, respectively...

A novel technique to modify the surface of calcium carbonate (CaCO3) nanoparticles, used as an antioxidant and reinforcing filler, by gallic acid is disclosed. The new properties of the modified CaCO3 could make it more useful and practical for the rubber industry. Thermal gravimetric (TGA), Fourier transform infrared spectroscopy, and transmission...

Due to the differences in unsaturation levels of constituent rubbers, thioacetate and mercapto functional groups were introduced into hydrogenated natural rubber (HNR) to increase the compatibility of natural rubber (NR)/HNR blends. The effect of thioacetic acid and initiator concentrations including reaction time on the thioacetate content in HNR...

The present work aims at exploring a new hydrolysis approach using sequential combinations of organic acid [oxalic acid (OA)] and base [tetramethylammonium hydroxide (TMAH)] to convert lignocellulosic biomass at mild conditions (150−215 °C, 1−2 h, and 1 atm N2) using a spruce wood sample in a batch reactor. In the single-step tests, hydrolysis with...

The liquefaction of sugar cane bagasse in supercritical ethanol, with or without various proportions of water as a proton donor, was conducted in a batch reactor to evaluate the optimal conditions for bio-oil production. The following variables were studied: temperature, initial H2 pressure, and catalyst type (FeS, Fe2S3/AC, and FeSO4). For noncata...

Unsupported NiMo sulfide catalysts were prepared from ammonium tetrathiomolybdate (ATTM) and nickel nitrate by using a hydrothermal synthesis method involving water, organic solvent and hydrogen. The activity of these catalysts in the simultaneous hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was...

In situ silica filling of styrene grafted natural rubber (ST-g-NR) was carried out by using sol-gel reaction of tetraethoxysilane (TEOS). The effects of concentration of catalyst and reaction temperature on the in situ silica content were investigated. ST-g-NR was synthesized via an emulsion polymerization using cumene hydroperoxide (CHPO) and tetr...

The mechanical properties of brittle polymers are improved by blending with rubbers. Due to C=C in the rubber structure, polymer/rubber blends have poor thermal and oxidative resistance. In this research, the mechanical and physical properties including the morphology of poly(methyl methacrylate-co-styrene) sheet modified by blending with hydrogena...

The in situ silica filling of natural rubber (NR) was carried out via the sol–gel reaction using tetraethoxysilane. The effect of the in situ silica content on the curing, mechanical, dynamic mechanical and thermal properties of the composite vulcanizate materials was investigated in comparison to that with a commercial silica preparation. The Moon...

The physical, chemical and thermal properties of diene-based polymers are improved by a chemical modification method such as hydrogenation. Skim natural rubber (SNR) which is mainly comprised of cis-1,4-polyisoprene was hydrogenated by diimide reduction in latex form, using hydrazine and hydrogen peroxide with copper sulfate as catalyst. The effect...

Hydrogenated natural rubber (HNR) prepared from natural rubber (NR) is a new sustainable elastomer with excellent thermal properties. This study reports on the effect of vulcanization system and blend ratio on the thermal and oxidative resistance of HNR/NR vulcanizates. The various HNR/NR ratios vulcanized by peroxide and sulfur donor system exhibi...

OsHCl(CO)(O2)(PCy3)2, was used as a catalyst for hydrogenation of styrene-g-natural rubber copolymer (ST-g-NR). Univariate experiments were conducted to explore the effect of variables on the rate of hydrogenation by measuring the hydrogen consumption as a function of time using a gas-uptake apparatus. From the kinetic results, the hydrogenation of...

The cure characteristics and mechanical properties of blends consisting of hydrogenated natural rubber (HNR) and natural rubber (NR) blends were investigated. The HNR/NR blends at 50/50 wt ratio were vulcanized using various cure systems: peroxide vulcanization, conventional vulcanization with peroxide, and efficient vulcanization with peroxide. Th...

Natural rubber latex (NRL) is comprised of cis-1,4-polyisoprene as the major component which has poor resistance to oxidation and degradation by ozone and long-term heating due to the presence of carbon–carbon double bonds in the polymer backbone. Hydrogenation is a useful method, for improving the oxidative and thermal degradation resistance of di...

The synthesis of nanosized polyisoprene latex was carried out by differential microemulsion polymerization using 2, 2′-Azoisobutyronitrile (AIBN) initiator system under various reaction conditions. A fractional factorial experimental design was applied to study the effects of reaction variables: amount of initiator and surfactant, monomer-to-water...

Extraction as a means fof material recovery is an economical utilization of natural resource.An investigation into efficient extraction technique,less expensive and reusable working substance and minimal energy consumotion is direction of this research. Cloud point extraction [CPE] is a novel technology with an adventage of being applicable at room...

Removal of organic sulfur compounds by using an adsorption process was carried out at ambient temperature and pressure. FAU zeolites, including NaY, HUSY cation-exchanged with metal ions such as Cu, Ni, Zn, and La, have been applied as adsorbents in the desulfurization of model and real transportation fuels. The results showed that the type of meta...

Zeolites have been hydrothermally synthesized using Thai coal fly ash from Mae Moh Power Plant as silica and alumina sources. The synthesis conditions, i.e., SiO2/Al2O3 ratio, amount of water, amount of base, and aging temperature, were varied to prepare different topologies of zeolitic products. The zeolites attained were sodalite (SOD), gismondin...

The graft copolymerization of methyl methacrylate onto natural rubber (NR) was carried out by using cumene hydroperoxide as redox initiator. The monomer conversion, grafting efficiency, and graft copolymer composition were examined. The purified graft copolymer was then hydrogenated by using a homogeneous osmium catalyst, OsHCl(CO)(O2)(PCy3)2. The...

The graft copolymerization of methyl methacrylate onto natural rubber was carried out by using a cumene hydroperoxide redox initiator. The graft copolymer was purified by extraction and then hydrogenated in the presence of OsHCl(CO)(O2)(PCy3)2. The graft copolymer and hydrogenated product were characterized by proton nuclear magnetic resonance (1H...

The purpose of the present work was to investigate the catalytic hydrogenation of natural rubber in the presence of palladium deposited on barium sulfate (Pd/BaSO4). The resulting polymeric structure was determined via 1H-NMR spectroscopy. It was found that the structure of the rubber product was formed as a result of competitive reactions: hydroge...

In this study, the in situ silica was generated in natural rubber by sol-gel reaction. The effects of solvent, catalyst type and concentration, mole ratio of tetraethoxysilane (TEOS) to water, and reaction temperature on in situ silica formation were investigated. TEOS was used as the precursor for silica generation. N-butylamine and n-hexylamine w...

This paper reports on a comparative study of unsupported MoS2 and Me/MoS2 (Me = Co, Ni) catalysts prepared by hydrothermal synthesis in our laboratory. Hydrothermal synthesis using water and organic solvent under hydrogen was found to produce highly active Mo based sulfide nano-size particles. MoS2 had high surface area (320 m2/g) and large pore vo...

Extraction of Mae Moh lignite using toluene–tetralin mixture was performed in a batch reactor at a temperature range from 370 to 490°C and under initial hydrogen pressure up to 12MPa. Experiments were carried out to investigate the effects of temperature and initial hydrogen pressure on coal conversion, liquid yield and liquid composition. The effe...

Hydrogenation is one important method of chemical modification, which improves the physical, chemical and thermal properties of diene-based elastomers. Natural rubber latex (NRL) could be hydrogenated to a strictly alternating ethylene-propylene copolymer using a diimide reduction system. The diimide reduction technique of NRL was accomplished by u...

The mechanical properties of a modified acrylic sheet prepared by bulk copolymerization of methyl methacrylate (MMA) and styrene (ST) were improved by the addition of a small amount of graft natural rubber (GNR). The graft copolymerization of MMA and ST onto natural rubber latex was carried out by emulsion polymerization using potassium persulfate...

Hydrogenation is an important method of chemical modification, which improves the physical, chemical, and thermal properties of diene-based elastomers. Natural rubber latex (NRL) could be hydrogenated to a strictly alternating ethylene–propylene copolymer using diimide generated in an in situ system. The diimide generated using the in situ techniqu...

Effects of cumene hydroperoxide (CHPO)/tetraethylene pentamine (TEPA), tert-butyl hydroperoxide (TBHPO)/TEPA, and potassium persulfate (K2S2O8)/sodium thiosulfate (Na2S2O3) redox initiator on methyl methacrylate (MMA) grafted natural rubber by emulsion polymerization were investigated. The optimum reaction condition for each redox initiator on the...

The homogeneous catalyst precursor, OsHCl(CO)(O2)(PCy3)2, was utilized for the hydrogenation of natural rubber to convert the unsaturated structure to a saturated form, providing an alternating ethylene-propylene copolymer. A detailed kinetic investigation was carried out by monitoring the amount of hydrogen consumption during the reaction using a...

In the presence of chlorinated solvents, the catalytic complex [Ir(COD)py(PCy3)]PF6 (where COD is 1,5-cyclooctadiene and py is pyridine) was an active catalyst for the hydrogenation of synthetic cis-1,4-polyisoprene and natural rubber. Detailed kinetic and mechanistic studies for homogeneous hydrogenation were carried out through the monitoring of...

The graft copolymerization of styrene (ST) and methyl methacrylate (MMA) onto styrene–butadiene rubber (SBR) latex prepared by seeded emulsion polymerization has been studied under various reaction conditions using cumene hydroperoxide redox initiator. The mechanism of graft copolymerization has been investigated. The synthesized graft copolymers w...

Hydrogenation is an important method of chemical modification, which improves the physical, chemical, and thermal properties of diene elastomers. Natural rubber latex (NRL) can be quantitatively hydrogenated to provide a strictly alternating ethylene–propylene copolymer using a homogeneous osmium catalyst OsHCl(CO)(O2)(PCy3)2. A detailed kinetic in...

Liquefaction of Banpoo coal and Mae Moh coal using supercritical toluene–tetralin mixture was performed in a semi-continuous apparatus at a temperature ranging from 370 to 490 °C and under pressures up to 12.2 MPa. The addition of tetralin to toluene increased the coal conversion and the liquid yield by the stabilization of radical fragments and in...

Hard-coating suspensions for improving the scratch resistance of poly(methyl methacrylate) (PMMA) surfaces have been developed by a sol–gel processing method of silatrane in the presence of 3-glycidoxypropyl-trimethoxysilane (GPTS) using 1 M HCl as a catalyst. Poly(methyl methacrylate) substrates were dipped into the coating solutions and dried at...

Ru[CHCH(Ph)]Cl(CO)(PCy3)2 (where PCy3 is tricyclohexylphosphine) functions as an efficient catalytic system for the hydrogenation of natural rubber. Furthermore, the addition of an acid plays an important role in promoting the hydrogenation process. The quantitative hydrogenation of natural rubber results in a polymer akin to an alternating ethylen...

Graft copolymer of glycidyl methacrylate and styrene onto natural rubber latex was synthesized by emulsion polymerization using cumene hydroperoxide and tetraethylene pentamine as a redox initiator. The effects of initiator and monomer concentration, reaction temperature and time on grafting efficiency and monomer conversion were investigated. The...

To improve the mechanical properties of poly(vinyl chloride) (PVC), the possibility of combining PVC with elastomers was considered. Modification of natural rubber (NR) by graft copolymerization with methyl methacrylate (MMA) and styrene (St) was carried out by emulsion polymerization by using redox initiator to provide an impact modifier for PVC....

The kinetics of the hydroformylation of high-molecular-weight cis-1,4-polybutadiene in the presence of HRh(CO)(PPh3)3 and monochlorobenzene as a solvent were studied. The degree of conversion was examined by spectroscopic characterization with Fourier transform infrared and 1H-NMR analysis. According to the 24-factorial experimental design, the tem...