Sa-Ad Riyajan

Thammasat University · Department of Chemical Engineering

This research intended to improve the hydrophilic behavior of starch-based films in food packaging by using surface coating with maleated epoxidized natural rubber (MENR) and then mechanically reinforced film through compositing with cellulose additive addition. The biocomposite was created from cellulose fiber (CF) and cassava starch (CS) by using...

This work reported the production of epoxidized natural rubber (ENR)/poly (vinyl alcohol) (PVA)/graphene (rGO) composite by latex mixing method. The particle size of rGO was about 740 nm and negative charge value (−29 mV). After the incorporation of the rGO into the 80/20 ENR/PVA blend, the color turns into black. The toluene resistance was also im...

Cassava starch (CS) has poor water resistance and it is limited to use in applications such as food packaging and medical materials. Lactic acid (CL) modified cellulose was used to improve the properties of CS. In particular, incorporating CL in CS significantly improved the water resistance and mechanical properties. The ester linkage of this samp...

The environmental-friendly and sustainable development is a top concern of rubber industry. Here we reported a green method to fabricate a class of epoxidized natural rubber (ENR) by employing many amino acids as a self-crosslinker. Moreover, the covalent crosslinks result in strong interfacial interaction between plant amino acid (PAA) and ENR, en...

The objective of this work was to prepare a maleate epoxidized natural rubber (MENR) and poly(vinyl alcohol) (PVA) (MENR/PVA) blend in the presence of ascorbic acid (AA). Firstly, the MENR was synthesized using maleic anhydride (MA), epoxidized natural rubber (ENR) latex and potassium persulfate as an initiator. Then, the MENR was blended with PVA...

Green polymer is made from epoxidized natural rubber (ENR) latex (natural polymer plant), N-vinylcaprolactam (NVCL), and poly (vinyl alcohol) (PVA). Firstly, NVCL was grafted onto the ENR using potassium persulfate as an initiator and its chemical structure was confirmed using ATR-FTIR and ¹H NMR. The graft copolymer occurs at amorphous (non-crysta...

Temperature-responsive polymers are smart materials due to responding to change in surrounding temperature and are applicable for different applications. Here, we prepared the smart rubber from epoxidized natural rubber (ENR) latex, N-vinylcaprolactam (NVCL) as monomer, poly(vinyl alcohol) (PVA) as a surfactant and potassium persulfate (KPS) as fre...

A highly efficient method was developed to produce a new biocomposite (PF) from waste paper and sugar cane stalk (SF) using four types of adhesive: maleated poly(vinyl alcohol) (PVAM), natural rubber-graft-cassava starch (NC), modified cassava starch (SA) and a blend between the NC and SA (NS). The effects of adhesive type and concentration, and th...

A novel macroporous material was fabricated at ambient temperature from maleate epoxidized natural rubber (MENR), and poly (vinyl alcohol) (PVA), using modified cellulose (MC) as a cross-linker and blowing agent. The effects of differing MC contents on the physical properties, such as the moisture content, moisture absorption, swelling ratio, tensi...

The objective of this work was to prepare functionalized cellulose fiber from sugar cane leaf (SCF) used to produce novel biomaterial. The SCF was treated with chloroacetic acid and sodium hydroxide (NaOH) to produce a modified cellulose fibre (MSCF). At higher MSCF loading, a greater porous density was observed under SEM. The addition of MSCF impr...

The biocomposite was made from the blend of carboxylated styrene-butadiene rubber (CSBR), cassava starch (CS) and cellulose fiber (CF). Coating of the CSBR onto the CSBR/CS/CF biocomposites by immersion method which produced the CSBR-coated CSBR/CS/CF composites with improving the water resistance, moisture content, and moisture absorption. The con...

Nowadays, hydrogels are widely used in many fields, for instance as biosensors, in tissue engineering and in agriculture due to their high swelling behavior in water and their softness. The objective of this work was to study the preparation and physical properties of maleated poly (vinyl alcohol) (PVAM)-graft-butanediol (BDO) (PVAM-graft-BDO) usin...

Hydrogels are widely used in medical, food and other applications due to their good water absorption without dissolution. The objective of this work was to synthesize a maleated poly(vinyl alcohol) (PVAM) grafted copolymer with anionic polyacrylamide (PAM) (PVAM-graft-PAM) using K2S2O8 as an initiator in an eco-friendly process. The chemical struct...

Maleate poly (vinyl alcohol) (PVAM)-graft water soluble polymer with deproteinized natural rubber (DPNR) porous materials were prepared using the freeze drying technique. The effect of the water soluble polymer type (chitosan (CS) and gelatin (GT)) and the DPNR content was studied. The mechanical properties of the porous materials were improved by...

The objective of the work described was to study the preparation of a novel polymer composite from gelatin (GT), natural rubber (NR) and bagasse cellulose (BC) using potassium persulphate as an initiator, and urea (U) as a plasticizer. The results showed that the moisture content, moisture absorption and swelling ratio decreased as a function of th...

Many polymers have been used to develop biodegradable films but starch is an attractive material for this purpose because it is an abundant renewable and low cost material. In this study, the effect of glycerol (GE) as a plasticizer on the physical properties of carboxylated styrene-butadiene rubber/cassava starch blend films was investigated. The...

A novel polymer was made from a blend between cassava starch (CS) and carboxylated styrene-butadiene rubber latex (CSBR) (CS/CSBR) blend in the presence of potassium persulfate (K2S2O8) using the aqueous solution-latex method. The effects of CS content, K2S2O8, reaction time, and temperature on the %gel content of the CS/CSBR blend were investigate...

The objective of the present work was to study the preparation of a novel bio-based product from gelatin (GT) and natural rubber (NR) using potassium persulphate (KPS) as an initiator. The GT and NR composites (GT/NR composites) containing KPS were formed in an aqueous latex solution. The chemical structure of the GT/NR composite was characterized...

Currently, there is an environmental pollution problem generated in part by packaging materials produced from non-biodegradable synthetic polymers made from petroleum. However, these can be replaced with biodegradable materials made from cassava starch (CS) and natural rubber (NR). In the work described, a novel biopolymer film was obtained from th...

Wheat gluten based bioplastics with shrimp shell waste filler were prepared using compression molding. The effects of various amounts (0, 2.5, 5.0, 7.5 and 10 wt%) of shrimp shell powder and calcined shrimp shell powder on the tensile, morphological, thermal properties, and degradation of wheat gluten composites were investigated. The addition of s...

A novel herbicide bead was developed by phase separation, utilizing modified cassava starch (CSt), sodium alginate (SA) and 2,4-dichlorophenoxy acetate (2,4 DA), and the beads were also coated with natural rubber grafted with cassava starch (NR-graft-CSt) to aid their water resistance. The alginate gel beads with 65% entrapped 2,4 DA showed 90% rel...

The objectives of this work were to improve the properties of starch foam modified with egg shell and shrimp shell, and to compare with the effects of modification with commercial calcium carbonate. The amount of these fillers added to the starch foam was in the range of 5 wt% to 20 wt% (dry starch basis). All the starch foams were prepared using a...

In this work modified fish scale waste (FS) was used as a filler in order to improve the properties of starch foam prepared by a baking process. The FS was modified under two calcination conditions: at 500 °C for 5 h and at 700 °C for 3 h. The FS powder calcined at 700 °C for 3 h (FS700-3) had higher Ca content and lower protein content and was the...

The objective of this study was to prepare the wheat gluten based bioplastics with fish scale (FS) through compression molding. The tensile strength of the wheat gluten/FS composites (the range of 6.5-7.5 MPa) was higher than that of the neat wheat gluten-based bioplastic (3.40 MPa). There was a good dispersion of the fish scale powder embedded wit...

A novel pH–temperature-sensitive elastomer was made from maleate poly(vinyl alcohol)-graft-isopropylacrylamide (PVAM-graft-PNIPAM), namely PVNI and deproteinized natural rubber (DPNR) in a water-based system. The swelling ratio in water of PVNI/DPNR hydrogel enhanced as a function of PVNI portion in hydrogel due to increasing of hydrophilic group i...

A novel bead of modified starch for encapsulating 2,4-dichlorophenoxy acetate (2,4 DA) was made from natural rubber-graft-cassava starch (NS) and sodium alginate (SA) in a water-based system. The particle size and zeta potential of pristine NS, the NS/SA blend and the NS/SA blend containing 2,4 DA were evaluated. The swelling ratio in water of the...

The objective of this work was to study the mechanism of gel formation for maleated poly(vinyl alcohol) (PVAM) and maleated poly(vinyl alcohol)-graft-gelatin (PVAM-g-GT) in solution form using a rheometer to monitor changes in the dynamic viscosity and shear stress-shear rate curves. The dynamic viscosity of the PVAM solution increased with increas...

To date, smart hydrogels are widely used in the biomedical field such as wound dressings, artificial tendons, drugs and tissues owing to its sensitivity on environmental medium. The present work was focused on the preparation of a maleated poly(vinyl alcohol) (PVAM)-g-gelatin (GT) (PVAM-g-GT) from the PVAM and the GT in aqueous solutions using K2S2...

The objective of this work was to study the preparation of novel foam prepared from natural rubber grafted with cassava starch (NR-graft-CSt) with the addition of super cell (SC) as a blowing agent. The effects of the blowing agent and grafting versus non-grafting of the starch and the natural rubber on the properties of the foam were investigated....

The aim of this work was to prepare and characterize the nanofiber obtained from epoxidized natural rubber-g-chitosan (ENR-g-CTS)/poly(vinyl alcohol) (PVA) blends. The preparation of ENR-g-CTS/PVA blend nanofibers was carried out using the electrospinning technique. The morphology of the ENR-g-CTS/PVA blend nanofiber was confirmed by SEM, TEM and A...

The turmeric extract nanoparticles were synthesized by complexation involving modified carboxylmethyl cellulose (MCMC) and calcium ions. The effect of viscosity of carboxylmethyl cellulose (CMC) solution on the particle size of turmeric extract nanoparticle was investigated. Firstly, MCMC viscosity decreases with the increase of H2O2 content (as ob...

A maleated poly(vinyl alcohol) (PVAM)-g-chitosan (CS) (PVAM-g-CS) film was prepared in solution form using potassium persulfate (K2S2O8) as an initiator. The influence of the PVAM:CS ratio, the reaction time and temperature and the concentration of K2S2O8 on the properties of the PVAM-g-CS were investigated. Ether linkage of the PVAM-g-CS was obser...

Rubber wood sawdust (RS) was used as a filler to improve the water absorption, mechanical, morphological, and thermal properties of thermoplastic starch (TPS). The TPS/RS composites were prepared using compression molding and glycerol as the plasticizer. Moreover, the effect of commercial cellulose (CC) on the properties of TPS was also studied for...

The application of starch based materials for packaging purposes has attracted significant interest because they are both cheap and renewable resources. The study investigated the preparation and properties of a novel biopolymer sheet produced from a blend of maleated epoxidized natural rubber (MENR) and natural rubber-g-cassava starch (NR-g-CSt)....

This work aimed to study the properties of epoxidized natural rubber (ENR) having 19% mole epoxidation crosslinked with glutaraldehyde (GA) and its application in encapsulation of carbendazim (CAD). The swelling ratio in toluene and the elongation at break of cured ENR decreased with increasing dipping time in GA and the GA concentration. The weigh...

The objective of this work was to use by-products from the chemical degradation of polyurethane foam waste (w-PUfd) and blend them with an epoxidized natural rubber (ENR), named PENR, for improving the mechanical properties of a Standard Thai rubber 5L (STR 5L). The swelling ratio in toluene of the PENR decreased as a function of w-PUfd content due...

To date, the biopolymer is attractively used to blending with natural rubber (NR) to enhance its mechanical properties and biodegradable ability. Therefore, the objective of this work is to study the preparation of biopolymer composite from NR and coconut meal waste (CF filler) by using maleic anhydride (MA) as a crosslinking agent. The hardness an...

A novel pH-sensitive graft copolymer (PVAM-g-CSt) was synthesized from maleated poly(vinyl alcohol) (PVAM) and cassava starch (CSt) through a grafting reaction using potassium persulfate as a thermal initiator. The chemical structure of the PVAM-g-CSt was revealed by FTIR and ether linkage of the graft copolymer was observed at 1089cm(-1). The degr...

The objective of this present work was to prepare the epoxidized natural rubber (ENR)-g-maleic anhydride (MA) (ENR-g-MA) polymer, from ENR latex using K2S2O8 as an initiator. The chemical structure of the ENR-g-MA was confirmed by FTIR. The evidence for formation of a graft copolymer was found at 1,790 cm(-1) owing to the chemical reaction between...

The green composite was made from low grade natural rubber (LNR), cassava starch (CSt) and palm fiber by using two-roll mill and compression molding. Before adding palm fiber, the elongation at break of LNR/CSt blend was improved as a function of CSt content due to plasticizer of CSt. After chemical modification of palm fiber, SEM indicated the sig...

The preparation of biodegradable polymer blend was made from natural rubber (NR) latex, starch solution and poly (vinyl alcohol) (PVA) solution by a latex-solution casting method. The swelling ratio of the polymer blend dramatically decreased as a function of silica content and NR content. With the increase in silica content, the tensile strength a...

The grafting of a modified cationic polyacrylamide (MCPAM) onto natural rubber (NR) latex to forma copolymer using potassium persulphate (K2S2O8) to generate active radicals on both the NR particle surface as well as on the MCPAM molecules was confirmed by ATR-FTIR. The copolymers showed a marked ability to absorbe palm oil up to 10 g g-1. First, t...

The objective of this work was to synthesize maleated poly(vinyl alcohol) (PVAM) in aqueous solution through esterification, and to seek near optimal degree of grafting and crosslinking. The effects of maleic anhydride (MA) content on the properties of PVAM were investigated. The experimental observations included characterizations by ATR-FTIR and...

The aim of this work was to prepare a NR latex coagulant from cationic polyacrylamide (C-PAM) using K2S2O8as an initiator. The influence of the K2S2O8content, temperature, reaction time and C-PAM concentration on the solubility of C-PAM was investigated by observations of its dynamic viscosity. The optimal conditions for preparing C-PAM were invest...

The effects of K2 S2 O8 , palm fiber length and maleic anhydride (MA) on the physical properties of the green composite made of low grade natural rubber (LNR), cassava starch (CSt) and palm fiber prepared by using two-roll mill and compression molding were investigated. The tensile strength of LNR/CSt composite containing 10% palm fiber with < 450...

A novel composite adsorbent in the form of beads for removal of Pb2+ from wastewater was prepared by blending a sodium alginate (NaAlg) solution, natural rubber (NR) latex, and coconut waste (cofiber). After being crosslinked by calcium chloride, the beads were highly stable, flexible, and easily used in the environment. The optimum composition of...

The objective of the present work was to study the vulcanization of epoxidized natural rubber (ENR) latex using terephthalic acid (TA) as a novel crosslinker. The influence of TA on the physical properties including the swelling behaviour, tensile strength and thermal stability of the cured ENR, which was compressed at 180°C for 30 minutes, was stu...

Novel biopolymer hydrogels were made from poly(vinyl alcohol) (PVA), epoxidized natural rubber (ENR) and starch with glutaraldehyde (GA) as a crosslinking reagent. The swelling ratio of the polymer hydrogel decreased as a function of the GA content, ENR content, PVA content, glycerol content while the swelling behavior of the new polymer hydrogel i...

The objective of this present work was to the preparation of polymer composite from low grade natural rubber (LNR), cassava starch (CSt) and palm fiber by using two-roll mill and then compression molding. The surface of palm fiber with different palm fiber lengths was analyzed by SEM. The tensile strength of the LNR/CSt composite containing 10% pal...

The polymer blend was prepared from the wastes of natural rubber glove (NRG) and polystyrene foam (PSf) blended with cellulose via brabender method. NRG was masticated by two-roll mill at ambient temperature, and then blended with PSf with or without sugar cane leave fiber (fsu) by brabender at 120°C. Then, the polymer blend sheet was continued to...

The aim of this work was to prepare a carrageenan-g-poly(vinyl alcohol) (CG-g-PVA) polymer using potassium persulphate as an initiator. The effect of different ratios of the polymer blends on the parameters of the grafted polymer was investigated. The grafting ratio decreased with an increase of the CG content in the graft copolymer. The resulting...

This study examined the effect of natural rubber (NR) on the properties of a biopolymer hydrogel produced from polyacrylamide (PAM) and starch (St) with microwave assistance. The main factors including the polymer blend ratio, the NR content, and the maleic anhydride (MA) content which affected the properties of the hydrogel samples were investigat...

The objective of this study was to develop a pressure sensitive adhesive (PSA) from epoxidized skim rubber (E-LPSR) obtained from saponified low protein skim rubber (S-LPSR) and blended with poly (vinyl alcohol) (PVA) containing a tackifier, via solution and emulsion, respectively. The creep properties of PSA and E-PSA in the presence of a 60 hydro...

The epoxidized natural rubber (ENR) latex-g-chitosan (ENR-g-chitosan) was prepared in latex form using potassium persulphate as an initiator. Firstly, the reduction in molecular weight of chitosan was subjected to the addition of K2S2O8 at 70°C for 15min. The structure of the modified chitosan was characterized by ATR-FTIR. Secondarily, the influen...

The maleated sulfur prevulcanized natural rubber grafted cellulose (M-SPNR-g-cellulose) was prepared from SPNR latex and cellulose fiber of corn leaves by using benzoyl peroxide and potassium persulfate as thermal initiators. The chemical structure of the M-SPNR-g-cellulose was confirmed byATR-FTIR and solid state 13C-NMR. Their modulus and hardnes...

Novel turmeric extract-coconut (c) oil nanoemulsion or particles were obtained from Tween 80 and Pluronic F 127 as a non-ionic surfactant by using high pressure homogenizer and followed coating with modified sodium alginate (NaAlg) for colon cancer therapy. Firstly, the NaAlg was modified with acetic acid, melon juice and H2O2 by microwave to reduc...

Turmeric extract (tmr) loaded nanoparticles were prepared by crosslinking modified carboxylmethyl cellulose (CMC) and modified sodium alginate (SA) with calcium ions, in a high pressure homogenizer. The FTIR spectra of CMC and SA were affected by blending due to hydrogen bonding. The negative zeta potential increased in magnitude with CMC content....

Pressure-sensitive adhesives (PSAs), or self-adhesives, are used in many applications, including safety labels for power equipment, automotive interior trim assembly, and sound/vibration damping films. The objective of this study was to develop a biodegradable skim rubber based bioadhesive blended with poly (vinyl alcohol) (PVA), which has the adva...

The maleated sulfur-prevulcanized natural rubber (M-SPNR) was prepared from grafting maleic anhydride (MA) onto SPNR latex particle by using benzoyl peroxide as an initiator. Natural rubber latex particle was vulcanized first, and then it was maleated to M-SPNR. The average particle size of M-SPNR was greater than that of SPNR possibly due to the f...

Biodegradable polymer blends based on poly (vinyl alcohol ) PVA, starch and epoxidized ENR natural rubber have been prepared. The polymer blend has been chemically surface modified by application of glutaraldehyde and formaldehyde in order to reduce water swelling. The modified polymer blend film has been investigated by swelling ratio in water, te...

The surface of natural rubber (NR) and epoxidized natural rubber (ENR) sheet modified with acrylic acid (ACC) and benzoyl peroxide as an initiator under UV irradiation to obtain NR-g-ACC and ENR-g-ACC sheet. The chemical structure of NR-g-ACC and ENR-g-ACC was confirmed by ATR-FTIR at 1740 (carbonyl group) and 3440 (hydroxyl) cm-1. The mechanical p...

The hydrophilicity of natural rubber (NR) was improved by grafting with modified cassava starch (ST) (NR-g-ST) by using potassium persulfate (K2S2O8) as a catalyst. The modified ST was added to NR latex in the presence of Terric16A16 as a non-ionic surfactant at 60 °C for 3 h and cast film on a glass plate to obtain NR-g-ST. The chemical structure...

The aim of this paper is to study the influence of the K2S2O8 content on the properties of poly (vinyl alcohol, (PVA). Firstly, PVA was dissolved in distilled water by heating by heating at 70 °C and then K2S2O8 was added in PVA solution under stirrer. The viscosity of PVA solution in the presence of K2S2O8 was analyzed by Brookfield Viscometers. T...

The polymer composite was prepared from the wastes of natural rubber glove (NRG) and polystyrene foam (PSF) blended with cellulose from sugar cane leaves via the laminate method. The NRG and PSF were firstly dispersed in toluene under continuous stirring. Then, maleic anhydride (MA) was added into the mixture. Effects of blend ratio and of MA conte...

The aim of this work is to study the influence of tea leave waste on the physical properties and vulcanization behavior of natural rubber (NR) compounds. The tea leave waste was modified by methyl methacrylate (MMA) and silane. The characterization of the modified tea leave waste was achieved with ATIR-FTIR and SEM. Results showed that the optimum...

The influence of PVA and cellulose on the properties of a PS/NR blend containing benzoyl peroxide and maleic acid as a crosslinking reagent was characterized by SEM, swelling ratio and hardness, tensile strength, DMTA and stress-strain behavior. The swelling of the polymer blend dramatically decreased after adding PVA. The hardness of the polymer b...

Bagasse was modified with sodium hydroxide and silane, and the obtained three polymer composite types, namely natural fiber, sugarcane bagasse, and plaster were procured by the two-roll mill method. The characterization of the modified sugarcane bagasse was achieved with attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR)...

This work describes the characterization and properties of a 'green' polymer blend based on epoxidized natural rubber (ENR) and PVA with maleic acid as a crosslinker. As observed from XRD patterns, the degree of crystallization of PVA decreases with an increasing starch content and maleic acid, due to the reactions between PVA, starch and maleic ac...

A biodegradable novel semi‐interpenetrating polymer network based on poly(vinyl alcohol) (PVA) and sodium alginate containing neem (Azadirachta indica) in the presence of azadirachtin‐A (neem Aza‐A) as well as glutaraldehyde as a crosslinking agent was prepared for use in the controlled released of neem Aza‐A. This is necessary because neem Aza‐A i...

Field NR latex was treated with various ammonia contents (0.35, 0.60 and 0.80% w/w) and then concentrated by centrifugation to 60% dry rubber content (DRC) and skim NR latex with roughly 5% DRC. The latex concentrate was adjusted to a high ammonia latex concentrate (HA latex) by adding NH3 to 0.65%-0.75% w/w of latex, ammonium laurate and water, th...

In der vorliegenden Arbeit wurden semi-interpenetrierende Polymernetzwerke (seim-IPN) aus NRund Polyvinylalkohol (PVA) oder epoxidiertem NR und PVA hergestellt um hydrophile Oberflächeneigenschaften zu erreichen. Die mechanischen Eigensschaften und die Quellbeständigkeit der mit Hillfe von Maleinsäure vernetzten semi-IPN wurden untersucht. Der Geha...

Natural rubber (NR) and its derivatives as renewable and biodegradable materials have attracted considerable attention because of the serious pollution problems caused by synthetic materials and a shortage of resources. A new semi-interpenetrating polymer network (semi-IPN) based on epoxidised natural rubber and polyvinyl alcohol containing maleic...

Neem extract containing Azadiractin-A (neem Aza-A), encased in microcapsules, in a matrix of partially hydrolyzed poly(vinyl acetate) crosslinked with glutaralaldehyde 5% (w/v) and 0.05% hydrochloric acid was prepared via a spray drying technique. The photostabilization of unencapsulated and encapsulated neem Aza-A when exposed to ultraviolet light...

At present, the use of huge quantities of synthetic pesticides in conventional agriculture has lead to some major environmental problems. Natural pesticide are now being developed to avoid such problems. Neem (Azadirachtin A) seed oil hereafter designated as neem Aza-A, is one such natural pesticide known to be a powerful insect antifeedant and gro...

The thermal decomposition behavior and degradation kinetics of natural rubber containing Poly(vinyl alcohol) (98% alcohol units) were investigated with thermogravimetric analysis under dynamic conditions at different heating rates. The derivative thermogravimetric curves showed that thermal degradation proceeds in one weight-loss step. The apparent...

The effect of ammonia treatment in field natural rubber (NR) latex with different storage period time on the properties of concentrated NR latex and stability of skim latex was investigated. Fresh NR latex was treated with various ammonia contents such as 0.35, 0.60 and 0.80% w/w, and then they were centrifuged to get the concentrated NR latex with...

The property of natural rubber (NR) is more interesting, except for some properties which need to improve. The cyclization reaction is an interesting reaction for modified NR to thermoplastic elastomer. The kinetic cyclization of deproteinized natural rubber (DPNR) or purified NR latex effectively performed in latex phase by using trimethylsilyl-tr...

Natural rubber (NR) and cyclized NR (90 % cyclization) were blended by dynamic vulcanization using a sulfur curing systems. The rate of vulcanization was slower in rubber blends containing cyclized NR was slower than the one of pure NR. Activation energies have been determined and the order of the thermal oxidative stability evaluated. It was seen...

Natural rubber (NR) and cyclized NR (C-NR) containing 5,20, and 90% degree of cyclization were blended by dynamic vulcanization in a high shear environment using sulfur based curing systems at 160°C. In addition, the addition of sulfur compound in C-NR (90%) latex before vulcanization process was also studied. As expected, all blends with curing ag...

Cyclization of deproteinized natural rubber (DPNR) or purified natural rubber latex was effectively performed in latex phase by using trimethylsilyl-trifluoromethane sulfonate or trimethylsilyl triflate (TMSOTF) as a novel catalyst, which is still not reported in the case of natural rubber latex. Various cyclization conditions affecting the degree...

Partially cyclized deproteinized natural rubber (DPNR) in latex form was successfully prepared by using a combination of sulfuric acid (H 2SO4) and benzotrichloride (PhCCl3) in the presence of Terric 320 as a non-ionic surfactant. The main parameters of the cyclization process such as various reaction times, dry rubber contents, concentrations of c...

Low molecular weight deproteinised natural rubber (LDPNR) was prepared by a new oxidative method using K2S2O8, and butanal as an organic solvent (swelling method). The efficiency of degradation was characterized by dilute solution viscosity and FTIR. The morphology and particle size were investigated by TEM. It was shown that the addition of organi...

Cationic cyclizationDeproteinized natural rubber latexSulfuric acid An increase in the plasticity of natural rubber (NR) to be a thermoplastic elastomer was carried out by cyclization reaction. The cyclized (NR) was obtained from deprotei- nized (NR) latex as a raw material, sulfuric acid as a catalyst, and Terric 320 as a non- ionic surfactant. Va...

The photodegradation of raw natural rubber and natural rubber compound film were studied using an artificial solar energy simulator. The properties of degraded rubber sheets containing benzophenone (BP) were determined by solution viscosity, 1H-NMR, and FTIR analyses. In the case of rubber compounds containing BP, the changes of tensile strength an...

Recently, natural rubber (NR) and its derivative as renew able and biodegradable material have attracted considerable attention because of the serious pollution problems caused by synthetic materials and shortage of resources. In the present study we prepare the semi-interpenetrating polymer network (semi-IPN) based on NR/polyvinyl alcohol (NR/PVA)...

The property of natural rubber (NR) is more interesting, excepting for some properties need to improve. The cyclization reaction is an interesting reaction for modified NR to thermoplastic elastomer. Cyclization of deproteinized natural rubber (DPNR) or purified NR latex was effectively performed in latex phase by using trimethylsilyl-trifluorometh...