Degradation Of Natural Rubber Research Articles

Insight into pyrolysis characteristic and mechanism of natural rubber using rapid infrared-heating fixed bed combined with pyrolysis kinetics

Pyrolysis is a potential approach to treat post-consumer waste natural rubber (NR), however, unclear pyrolysis mechanism restricts its actual utilization. In this work, thermal degradation of NR was investigated combining dynamical method with pyrolysis on the infrared-heating fixed-bed reactor. Results show that thermal degradation of NR is an apparently exothermic and multistep reaction, tar yield reaches up to 96.59 wt%. Pyrolysis tar mainly consists of cycloolefin with a small quantity of chain olefins and mono-ring aromatic hydrocarbons. High temperature reduces the cycloolefin yield but promotes the generation of mono-ring aromatic hydrocarbons. Tar is mainly composed of dimer (C10) or trimer (C15) of isoprene with different structures. H type in tar is mainly aliphatic hydrogen. Besides, a possible pyrolysis mechanism based on the β bond breakage was proposed. The work can provide a theoretical basis for direct control of high value-added products during NR pyrolysis and achieve high efficiency pyrolysis of NR.

Efficient degradation of vulcanized natural rubber into liquid rubber by catalytic oxidation

Waste tire rubber based on natural rubber (NR) represents an abundant feedstock for the production of valuable products. This study investigated an efficient approach to convert NR vulcanizates into liquid rubber with the number-average molar masses of 1.3 × 104 g/mol. Compared to the anaerobic liquefaction at 300 °C for 3 min, NR vulcanizates were liquefied efficiently at 210 °C for 3 min by thermo-oxidative degradation catalyzed by manganese (II) stearate. The apparent activation energy of the NR degradation reaction decreased from 470.8 kJ/mol to 208.2 kJ/mol with catalysis, which was attributed to the formation of a coordination complex between catalysts and peroxides via the single-electron transfer redox reaction, leading to the catalytic oxidative degradation of NR vulcanizates. The main chain scission and crosslink scission occurred simultaneously during the degradation process, and the main chain scission was the primary catalytic oxidation reaction according to the Horikx theory. In addition, the obtained liquid rubber contained carbonyls, ether linkages, and sulfoxide groups, as proved by FTIR and 13CNMR . The catalytic oxidative degradation mechanism of NR vulcanizates was proposed based on the chemical structure of products and simulation results. The efficient method was proposed to highly facilitate the recycling and valorization of NR-based waste tire rubber.

Preparation and Characterization of TiO2-Coated Hollow Glass Beads for Functionalization of Deproteinized Natural Rubber Latex via UVA-Activated Photocatalytic Degradation.

The photochemical degradation of natural rubber (NR) is a prevalent method used to modify its inherent properties. Natural rubber, predominantly derived from the Hevea Brasiliensis tree, exhibits an exceptionally high molecular weight (MW), often reaching a million daltons (Da). This high MW restricts its solubility in various solvents and its reactivity with polar compounds, thereby constraining its versatile applications. In our previous work, we employed TiO2 in its powdered form as a photocatalyst for the functionalization of NR latex. However, the post-process separation and reuse of this powder present substantial challenges. In this present study, we aimed to functionalize deproteinized NR (DPNR) latex. We systematically reduced its MW via photochemical degradation under UVA irradiation facilitated by H2O2. To enhance the efficiency of the degradation process, we introduced TiO2-coated hollow glass beads (TiO2-HGBs) as photocatalysts. This approach offers the advantage of easy collection and repeated reuse. The modified DPNR showed a reduction in its number-average MW from 9.48 × 105 to 0.28 × 105 Da and incorporated functional groups, including hydroxyl, carbonyl, and epoxide. Remarkably, the TiO2-HGBs maintained their performance over seven cycles of reuse. Due to their superior efficacy, TiO2-HGBs stand out as promising photocatalysts for the advanced functionalization of NR across various practical applications.

Degradation of Natural Rubber as Asphalt Mixes Modifier using UV-Ozone Light

The elastic properties of natural rubber are indispensable in improving the physical properties of asphalt mixtures. However, the long natural rubber molecule chains make it difficult to modify with other polymeric materials, so it needs to be degraded. In this study, the authors succeeded in degrading natural rubber using a combination of UV light and ozone with the addition of an H2O2 initiator; from the FTIR data, it appears that there are peaks indicating vibrations of the C=O and –OH groups indicating that natural rubber chain termination has occurred. The addition of natural rubber to asphalt was carried out with several variations, namely 8; 10; 12; 14; 16 % (to asphalt content), from the results of the softening point and ductility test of the asphalt mixture explained that the addition of 12 % natural rubber was the most optimum mixture. This result explains that efforts to degrade natural rubber using the UV - ozone combination method can increase the optimum insertion of natural rubber into asphalt mixtures by up to 100 % from previous studies.

Facile synthesis of nickel-based supported halloysite nanotube catalysts and their role in photocatalytic degradation of liquid epoxidized natural rubber

Facile synthesis of nickel-based supported halloysite nanotube catalysts and their role in photocatalytic degradation of liquid epoxidized natural rubber

Fabrication, characterization and mechanical properties of hematite (a-Fe2O3) filled natural rubber/low-density polyethylene composites

In this study, natural rubber (NR) and low-density polyethylene (LDPE) were melt blended in a 2-roll mill to fabricate NR/LDPE composites with liquid natural rubber (LNR) and hematite (a-Fe2O3) as compatibilizer and filler respectively. The effects of liquid natural rubber (LNR) on the mechanical properties and morphology of NR/LDPE composites were investigated. NR/LDPE composites were prepared in three different compositions of 70/30, 50/50 and 30/70, with filler content at varying concentrations (3, 5 and 7 g) while LNR was kept at 10 g for the modified composites. Results obtained showed increment in the tensile strength, tensile modulus, compressive and flexural properties but with decrease in the elongation at break the a-Fe2O3 and LDPE contents increase. The modification of the composites with LNR further enhanced the mechanical properties. FTIR spectrum of LNR revealed a peak at 3395 cm-1 suggesting the hydroxyl (OH) end group attached to the LNR chain due to the photochemical degradation of NR to yield LNR. FTIR spectra of the selected composites showed the presence of iron oxide bond (Fe-O) at 571 cm-1, 467 cm-1 and 463 cm-1 due to the incorporation of a-Fe2O3 filler particles in the composites. SEM images showed improved matrix/filler interfacial adhesion induced by the LNR compatibilizer.

Characterization of Latex-Clearing Protein and Aldehyde Dehydrogenases Involved in the Utilization of poly(cis-1,4-isoprene) by Nocardia farcinica NBRC 15532

Microbial degradation of natural rubber and synthetic poly(cis-1,4-isoprene) is expected to become an alternative treatment system for waste from poly(cis-1,4-isoprene) products including scrap tires. Nocardia farcinica NBRC 15,532, a gram-positive rubber-degrading bacterium, can utilize poly(cis-1,4-isoprene) as the sole source of carbon and energy to produce oligo-isoprene metabolites containing aldehyde and keto end groups. A homology-based search of the genome revealed a gene encoding a latex-clearing protein (Lcp). Gene disruption analysis indicated that this gene is essential for the utilization of poly(cis-1,4-isoprene) in this strain. Further analysis of the genome sequence identified aldehyde dehydrogenase (ALDH) genes as potential candidates for oxidative degradation of oligo-isoprene aldehydes. Based on the enzymatic activity of the ALDH candidates, NF2_RS14000 and NF2_RS14385 may be involved in the degradation of oligo-isoprene aldehydes. Analysis of the reaction products revealed that these ALDHs oxidized tri- to penta-isoprene aldehydes, which were generated by the reaction of Lcp. Based on the inability of ALDH gene deletion mutants, we concluded that NF2_RS14000 is mainly involved in the utilization of poly(cis-1,4-isoprene) and the oxidative degradation of oligo-isoprene aldehydes in Nocardia farcinica NBRC 15,532.

Natural rubber composites with antioxidant‐loaded activated calcium silicate for improved thermo‐oxidative aging resistance

AbstractGreen and low‐cost methods are required as alternatives to conventional approaches for impeding the thermo‐oxidative degradation of natural rubber (NR). Herein, to improve the dispersibility of N‐1,3‐dimethylbutyl‐N′‐phenyl‐p‐phenylenediamine (antioxidant 4020) and simplify the loading procedure, antioxidant 4020 was precipitated from acetone using activated calcium silicate (ACS), a byproduct of alumina extraction from fly ash, as a carrier. In the obtained antioxidant 4020‐loaded ACS (ACS‐4020) particles, which had a loading of 7.8%, the antioxidant was physisorbed on the surface of ACS with a uniform distribution. In composites with NR, ACS‐4020 was uniformly dispersed in the NR matrix via chemisorption. ACS‐4020/NR exhibited a faster vulcanization speed, better static mechanical properties, and greater thermal stability than the composite in which antioxidant 4020 was directly integrated (ACS/4020/NR). Changes in the tensile strength, elongation at break, hardness, and thermo‐oxidative aging degree of the composites at different aging times and temperatures showed that ACS‐4020/NR had enhanced resistance to thermo‐oxidative aging. Furthermore, the nitrogen‐containing compounds in ACS‐4020/NR were more stable and performed better against thermo‐oxidative aging. These findings can act as guidelines for the preparation of NR composites with superior thermo‐oxidative aging resistance.

Mechanical and Aging Properties of Hydrogenated Epoxidized Natural Rubber and Its Lifetime Prediction.

Natural rubber (NR) has restricted its application due to its potential for thermal- and oil-resistant materials. The weakness of NR can be eliminated by chemical modification to enhance aging properties. Formic acid and hydrogen peroxide have been used to prepare partially epoxidized natural rubber (ENR) in the latex state. Its residual unsaturated units were then modified using hydrazine and hydrogen peroxide to obtain hydrogenated ENR (HENR). 1H-NMR characterized the resulting products. NR and modified NRs were compounded and then vulcanized using a conventional milling process. This paper compares NR, ENR having 49.5% epoxide group content, and HENR having 49.5% epoxide group content and 24% hydrogenation degree in terms of tensile, thermal, oil, and ozone properties. Morphology and lifetime prediction were studied. Overall results show that the tensile strength of the HENR composite (14.7 MPa) was 79 and 71% lower than that of ENR (18.6 MPa) and NR (20.8 MPa) composites, respectively. In contrast, the modulus at 100% elongation of the HENR composite (2.0 MPa) was 167 and 200% higher than that of ENR (1.2 MPa) and NR (1.0 MPa) composites, respectively. Morphological studies of the tensile fractured surface of the vulcanizates, using scanning electron microscopy, confirmed a shift from ductility failure to brittle with the presence of the epoxide groups and low unsaturated bonds in the backbone chain. The results demonstrated that HENR could act as an ideal material, providing better thermal, oil, and ozone resistances while maintaining the mechanical properties of the rubber. The kinetic analyses of the thermal degradation of NR, ENR, and HENR were studied using thermogravimetric analysis (TGA) at three heating rates. Kissinger–Akahira–Sunose (KAS) was employed to calculate the activation energy (Ea). The obtained data were used to predict the lifetime under the established temperature range and 0.05 conversion level. Overall, the results represented that HENR had a longer lifetime than NR and ENR for a temperature range between 25 and 200 °C, indicating that HENR had excellent thermal stability than NR and ENR. Therefore, the HENR should extend the applications to include gaskets and seals, especially for the automotive and oil industries.

Effect of non-rubber components on the crosslinking structure and thermo-oxidative degradation of natural rubber

Non-rubber components (NRCs) in natural rubber (NR), including proteins, phospholipids, fatty acids, etc., determine to a large extent the structure and properties of NR. In this study, the effects of NRCs on the network structure and thermo-oxidative aging behavior of unvulcanized and vulcanized NR were investigated. NRCs were found to form physically crosslinked networks in the unvulcanized NR and acted as a natural antioxidant to scavenge free radicals, which contributed to improved thermo-oxidative stability of the unvulcanized NR. Swell analysis, chemical probe analysis (DPPH), and XPS results showed that the NRCs accelerated the vulcanization reaction and increased the crosslink density, and promoted the formation of more mono- and disulfide bonds during vulcanization. When aged at high temperatures, more monosulfide bonds were formed in the vulcanized rubber with high contents of NRCs by cleaving and rearranging the poly- and disulfide bonds. NRCs were also found to increase the activation energy of thermal degradation and led to the better mechanical stability of vulcanized NR against thermal oxidation.

Cationic waterborne polyurethane–chitosan based on natural rubber as new green antimicrobial coating

This is the first report on developing new methodologies to synthesize hydroxytelechelic natural rubber (HTNR), a bio-polyol based on natural rubber (NR), by mechanical and chemical degradation. The mechanical degradation of NR from shear during mastication leads to a lower molecular weight before oxidative cleavage by periodic acid. The effects of the molar ratio of periodic acid/isoprene unit ([H5IO6]/[isoprene unit]) on properties of HTNR were investigated. The end-functionality was determined by 1H NMR spectroscopy and the molecular weight was determined by SEC. The HTNR polyol with 3000 g/mol molecular weight and H5IO6 at 0.07 ratio were used as precursors to synthesize cationic waterborne polyurethane (cWPU). The cWPU had a well-defined size distribution and was stable for at least 3 months. The chemical structure of cWPU was confirmed by 1H NMR spectroscopy. Moreover, the hydrophilic properties and antimicrobial properties of cWPU improved when mixed with 1% solution of protonated chitosan (PCS). In addition, the effects of PCS content were studied. The investigations showed that increasing PCS gave a more hydrophilic surface with a low contact angle and a high surface free energy for the cWPU-PCS film. Furthermore, PCS at over 3%wt content inhibited E. coli growth. Hence, the new cWPU mixed with chitosan could serve as an alternative antimicrobial coating material.

Controlled degradation and functionalization of natural rubber by ozonolysis in organic solvent

Controlled degradation and functionalization of natural rubber by ozonolysis in organic solvent

Transformation of nitrogen, sulfur and chlorine during waste tire pyrolysis

The transformation of N/S/Cl during pyrolysis of waste tire were investigated by Thermogravimetry-Mass Spectrum (TG-MS) and flow tube furnace reactor. The pyrolysis of waste tire included four stages, i.e., dehydration below 200 ℃, decomposition of tire additives at 200∼300 ℃, degradation of natural rubber at 300∼420 ℃, and cracking of synthetic rubber at 420∼500 ℃. The activation energy Eα were calculated according to the Coats-Redfern integral method, ca. 154.72∼158.23 and 200.46∼231.58 kJ/mol for degradation of natural rubber and synthetic rubber, respectively. Most of nitrogen (60.32∼67.78 wt.%), sulfur (56.73∼62.38 wt.%), and chlorine (58.60∼64.92 wt.%) were remained in the pyrolytic char. For the pyrolytic oil composition, expect for alkanes, alkenes, aromatic hydrocarbons, and oxygenates, the S-containing disulfide and sulfurous acid ester, N-containing quinoline and pyrimidine diamine, and Cl-containing silane, dichlorododecylmethyl- were detected. The nitrogen, sulfur, and chlorine in pyrolytic gas had diverse types. The N-containing pollutants mainly derived from inorganic ammonium and heterocyclic-N. NH3 had a wide releasing temperature range, while NO, HCN, and HNCO were mainly generated at 300∼600 °C. The C–S and -SH radicals mainly contributed to S-containing pollutants, i.e., H2S, COS, CS2, SO2, CH3SH, and C6H5SH. The Cl-containing pollutants exhibited dominant release within the temperature range of 300∼600 °C. Overall, higher heating rate promoted gas emissions, especially for NO, HCN, CH3SH, and HCl. This article provides basic knowledge on hazardous N/S/Cl transformation in solid char, liquid oil, and gas during pyrolysis of waste tire that will provide valuable information for future control technologies of pollutants emission.

Controlling the characteristics of raw natural rubber by partial degradation in the latex stage using a water-soluble degrading agent

Partial degradation of high ammonia natural rubber (HANR) in the latex stage was successfully carried out in the presence of periodic acid as a water-soluble degrading agent at ambient temperatures, i.e. 30 °C. The number average molecular weight (Mn), weight average of molecular weight (Mw), gel content and Mooney viscosity were decreased as the periodic acid concentrations increased. The polydispersity was slightly increased with increasing periodic acid concentrations. The relationship between Mw, gel content and Mooney viscosity was established. Mw in the range of 8.0 × 105 g/mol to 1.2 × 106 g/mol, and gel content between 30 and 45 wt% successfully achieved the Mooney viscosity of raw natural rubber ranging from 60 to 85 MU. To obtain such properties, periodic acid concentration between 17 and 19 phr was used to partially degrade the natural rubber in the latex stage. The structural characterisations determined by Fourier transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopies confirmed the occurrence of chain scission to form carbonyl terminal groups as a result of partial degradation. In summary, the Mooney viscosity of raw natural rubber can be controlled by partial degradation of natural rubber in the latex stage, contributed by a controlled decrease in molecular weight and gel content. Hence, this work may be useful in altering the properties of raw natural rubber that are suitable for processing of dry rubber products.

Synthesis and characterization of natural rubber‐based telechelic oligomers via olefin metathesis

AbstractMetathesis degradation and functionalization of natural rubber (NR) were conducted with 1‐hexene, 1‐octene, 1‐decene, 1‐dodecene, trans‐stilbene, and 4,4′‐dibromo‐trans‐stilbene as chain transfer agents (CTAs) in presence of Grubbs 2nd generation catalyst to generate NR‐based telechelic oligomers that had been a long‐lasting challenge due to the structure and compositions of NR with various impurities. Orthogonal experiments were applied and the effects of the CTA type, CTA concentration, catalyst concentration, reaction time, and reaction temperature on the formation of telechelic oligomers were studied, indicating that the catalyst concentration was the major factor influencing the number average molecular weights (Mn) and polymer dispersity index (PDI) of telechelic oligomers. The structures of the oligomers were characterized using 1H NMR, 13C NMR, and MALDI‐TOF‐MS, which confirmed the formation of the designed terminal groups. The results showed that well‐defined telechelic oligomers with a Mn of a few thousand and a PDI around 1.6 were obtained, with potential applications in binder, lubricant and many other fields.

Characterization of the genes responsible for rubber degradation in Actinoplanes sp. strain OR16

A Gram-positive rubber-degrading bacterium, Actinoplanes sp. strain OR16 (strain NBRC 114529), is able to grow on agar plates containing natural and synthetic rubber as the sole sources of carbon and energy. When this strain was grown on natural rubber latex overlay agar plates, translucent halos around the cells were observed. To identify the natural rubber degradation genes and other features of its metabolism, its complete genome sequence was determined. The genome of OR16 consists of 9,293,892 bp and comprises one circular chromosome (GenBank accession number AP019371.1) with a G + C content of 70.3%. The genome contains 8238 protein-coding and 18 rRNA genes. A homology search of the genome sequence revealed that three genes (lcp1, lcp2, and lcp3) are homologous to an extracellular latex-clearing protein (Lcp) of Streptomyces sp. K30. RT-PCR analysis revealed that lcp1 and lcp2 seem to constitute an operon. Purified lcp gene products have oxygen consumption activity toward natural rubber latex, suggesting that all these genes encode rubber-degrading enzymes in OR16. Quantitative reverse transcription-PCR analysis indicated that the transcription of these genes is induced during the growth of OR16 on natural rubber. The genes located adjacent to lcp1 and lcp3, which code for a TetR/AcrR-type transcriptional regulator, can bind to the promoter regions of these lcp genes. It is suggested that the putative regulators play a role in regulating the transcription of the lcp genes. These results strongly suggested that three lcp genes are required for the utilization of natural rubber in strain OR16.Key Points• The complete genome sequence of Actinoplanes sp. strain OR16 was determined.• Three lcp genes which are involved in the natural rubber degradation in OR16 were identified.• Transcription of these lcp genes is induced during utilization of rubber in OR16.• Two regulators, which bind to the promoter regions of lcp, were determined.

Liquid guayule natural rubber, a renewable and crosslinkable processing aid in natural and synthetic rubber compounds

Liquid guayule natural rubber (LGNR) was produced by thermal degradation of guayule natural rubber and tested as a renewable alternative to naphthenic oil (NO) processing aid in natural rubber (Hevea and guayule rubber) and synthetic (styrene-butadiene) rubber composites filled with carbon black (CB). Processing oils are rubber additives commonly used to improve the processability of a compound. Most processing oils, like NO, are petroleum-based, and negatively impact the carbon footprint of the rubber industry. Moreover, these aids act as diluents that lower the mechanical performance of the resultant rubber products.The energy consumption of rubber compounding, mechanical properties and crosslinking networks of natural and synthetic rubber composites made with LGNR were characterized. LGNR effectively helped the compounds mix as demonstrated by 13–21% lower energy consumption compared to compounds mixed without processing aids. Moreover, unlike NO, LGNR acted as an active additive in the vulcanization reaction. Tensile strength, elongation at break, modulus at 100% strain and hardness increased when NO was replaced with LGNR in the compounds. The higher mechanical properties may be explained by additional crosslinking networks formed between LGNR and the rubber matrices and strong LGNR-CB interactions. LGNR, as a renewable processing aid, can address rising performance goals, and reduce carbon footprint for rubber products. In conclusion, LGNR provides the same benefits as conventional diluent processing aids, enhances the properties of the final material, and is produced from a renewable plant source.

Effect of triblock copolymers based on liquid natural rubber and low molecular weight poly(lactic acid) on physical properties of poly(lactic acid)/natural rubber blend

Triblock copolymers of poly(lactic acid) (PLA) and natural rubber (NR) (PLA–NR–PLA) with different lengths of PLA end blocks were produced from hydroxyl-terminated liquid natural rubber (HTLNR) and low molecular weight PLA (pre-PLA). The HTLNR with a number-average molecular weight $$(\bar{M}_{\text{n}} )$$ ~ 28,000 g/mol obtained from photochemical degradation of NR and pre-PLA with varying molecular weight ( $$\bar{M}_{\text{n}}$$ ~ 3000, ~ 6500, ~ 9700 g/mol) was subjected to condensation polymerization. The compatibilizing effect of copolymers on the physical properties of the PLA/NR blend was studied using PLA/NR/PLA–NR–PLA blend ratios of 90/10/0, 90/9/1, 90/8/2 and 90/7/3 percent by weight (wt%). From the tensile testing results, elongation at break of the blends increased with an increase in the amount of triblock copolymer and with the length of the PLA end block. The blend without the copolymer showed elongation at break of 60.54%, whereas the blend with 3 wt% of PLA–NR–PLA prepared from pre-PLA with $$\bar{M}_{\text{n}}$$ of ~ 9700 g/mol showed elongation at break of 199.38%. This was about a 300% increase. The highest impact strength of 79.58 kJ/m2 (400% higher than neat PLA) was also found for the blend containing 3 wt% of PLA–NR–PLA with the longest PLA end block. A reduction in the diameter and well dispersion of the rubber particles in the PLA matrix were seen in micrographs taken with a scanning electron microscope. In general, after the addition of PLA–NR–PLA into a PLA/NR blend, the Tg of NR phase shifted to a higher temperature, whereas the Tg of the PLA phase decreased. The PLA–NR–PLA triblock copolymer with the longest PLA end block is possibly used as an effective compatibilizer for the PLA/NR blend.

Ultrasonic Extrusion of NR Gum and Its Effect on the Structure and Properties of Unfilled and Silica‐Filled NR

Natural rubber (NR) has been extruded without and with ultrasonic treatment at various ultrasonic amplitudes. The effect of ultrasonic treatment on structure of NR, its compounds with silica and silica/silane and their vulcanizates have been studied. Processing‐structure‐properties relationship of untreated and treated materials has been established. With the increase of ultrasonic amplitude power consumption is increased and die pressure is reduced. Size exclusion chromatography measurements show that the NR molecular weight is reduced with the ultrasonic treatment. The storage modulus and loss modulus, complex viscosity and loss tangent results also confirmed the degradation of NR chains by imposition of ultrasound, especially after treatment at high amplitude. After mixing with silica and silica/silane, it was found that degradation of NR caused a reduction in the rubber–filler interaction, an increase in the filler–filler interaction and flocculation upon heating. Physical properties of vulcanizates including M100, ultimate elongation, and stress at break are also deteriorated. POLYM. ENG. SCI., 60:925–934, 2020. © 2020 Society of Plastics Engineers

Preparation and characterization of hydroxyl terminated liquid epoxidized natural rubber

Hydroxyl terminated liquid epoxidized natural rubber (HTLENR) was successfully synthesized via oxidative degradation of liquid epoxidized natural rubber (LENR) in the presence of cobalt (II) acetyl acetonate (CAA) as the oxidizing agent. The effect of reaction time on molecular weight, chemical structures and hydroxyl content of HTLENR were investigated. The weight average molecular weight (Mw) and polydispersity index (PDI) of the prepared HTLENR were determined using gel permeation chromatography (GPC). The result shows that as the reaction time increased, the Mw decreased indicating the occurrence of higher chain scission. It was found that the lowest Mw was achieved at 10 h reaction time where the Mw and Mn were 37,545 g/mol and 3,233 g/mol. The structural analysis and hydroxyl content of HTLENR on the other hand, were studied by using fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). The presence of OH group was confirmed by FTIR analysis with the appearance of broad peak at 3,200 - 3,600 cm-1. Subsequently, NMR analysis also confirmed that the highest amount of hydroxyl content which is 7.56 % was achieved at the longest reaction time which is 10 h.