Preparation of Cyclized Deproteinized Natural Rubber in Latex State via a Combination of Benzotrichloride and Sulfuric Acid System, and Its Properties

2007 ◽  
Vol 80 (2) ◽  
pp. 365-377 ◽  
Author(s):  
Sa-ad Riyajan ◽  
Yasuyuki Tanaka ◽  
Jitladda T. Sakdapipanich
Keyword(s):  
Sulfuric Acid ◽  
Natural Rubber ◽  
Reaction Times ◽  
Catalyst System ◽  
Proton Nuclear Magnetic Resonance ◽  
Ionic Surfactant ◽  
Gravimetric Analysis ◽  
Infrared Spectrometer ◽  
Deproteinized Natural Rubber ◽  
Better Than

Abstract Partially cyclized deproteinized natural rubber (DPNR) in latex form was successfully prepared by using a combination of sulfuric acid (H2SO4) 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 catalyst and temperatures were investigated. The resulting rubber was subjected to characterization by proton Nuclear Magnetic Resonance (1H-NMR), Fourier-Transform Infrared spectrometer (FTIR), Thermal Gravimetric Analysis (TGA), and Differential Scan Calorimeter (DSC). In addition, the topology of partially cyclized rubber was also analyzed by Transmittance Electron Microscopy (TEM). The mechanism will be also discussed. It was interesting to note that the obtained partially cyclized rubber using this catalyst system contained no gel, which was easily soluble in rubber solvents. This is different from the partially cyclized rubber obtained from the other methods. Through, using structural characterization, it was found that the PhCCl3 linked onto the rubber chain. It was also found that the thermal stability of this cyclized rubber was better than that of normal rubber. The efficiency of cyclization in this system could be increased by an increase of PhCCl3 concentration.

Effects of Type and Concentration of Initiator on Grafting of Acrylic Monomer onto Depolymerized Natural Rubber

2011 ◽  
Vol 264-265 ◽  
pp. 565-570 ◽  
Author(s):  
N. Prasoetsopha ◽  
Pranee Chumsamrong ◽  
Nitinat Suppakarn
Keyword(s):  
Natural Rubber ◽  
Epoxy Resin ◽  
Natural Rubber Latex ◽  
Reaction Times ◽  
Gel Permeation Chromatography ◽  
Renewable Resource ◽  
Good Evidence ◽  
Proton Nuclear Magnetic Resonance ◽  
Monomer Mixture ◽  
Air Oxidation

Highly crosslinked epoxy resin for engineering applications is normally stiff but brittle. Therefore, many attempts have been made to improve its toughness. Nowadays, several studies have been done on toughening epoxy resin using natural rubber (NR) because it is abundant and comes from renewable resource. In the present work, NR was subjected to depolymerize in order to achieve molecular dispersion of NR in epoxy matrix. Depolymerized natural rubber (DNR) was prepared by adding a carbonyl compound to natural rubber latex solution and subjecting the mixture to air oxidation in the presence of a radical forming agent at 70°C. In addition, the interfacial adhesion between rubber and matrix must be present to achieve a significant increase in toughness. Hence, DNR was further functionalized by grafting with monomer mixture of methyl methacrylate (MMA)/glycidyl methacrylate (GMA) (90/10 wt/wt%) in an amount of 50% based on rubber content. Solution polymerization was used to graft such monomers using 2 hours reaction times at a reaction temperature of 80oC. Two types of initiator used were benzoyl peroxide (BPO) and azo-bisisobutyronitrile (AIBN). The amounts of initiator in the grafting process were 1, 2, and 3 parts per hundred of DNR. Effects of type and concentration of initiator on grafting efficiency of MMA/GMA monomer mixture onto depolymerized natural rubber were studied by proton nuclear magnetic resonance (1H-NMR) analysis. The molecular weight of DNR was characterized by gel permeation chromatography (GPC). The results indicated good evidence for the formation of graft co-polymers in the presence of both initiators, AIBN or BPO. However, the amounts of grafted MMA/GMA on DNR backbone using BPO was higher than those on DNR backbone using AIBN.

scholarly journals Rapid four-component synthesis of dihydropyrano[2,3-c]pyrazoles using nano-eggshell/Ti(IV) as a highly compatible natural based catalyst

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Reaction Times ◽  
Diffraction Field ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Work Up

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.

Novel membranes from physico-chemically modified deproteinized natural rubber latex: development, characterisation and drug permeation

2018 ◽  
Vol 42 (17) ◽  
pp. 14179-14187
Author(s):  
Janisha Jayadevan ◽  
G. Unnikrishnan
Keyword(s):  
Drug Release ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Drug Permeation ◽  
Chemically Modified ◽  
Blend Membranes ◽  
Deproteinized Natural Rubber

Novel blend membranes from physico-chemically modified deproteinized natural rubber latex for drug release applications.

Molecularly Imprinted Polymers and Room Temperature Ionic Liquids: Impact of Template on Polymer Morphology

2007 ◽  
Vol 60 (1) ◽  
pp. 51 ◽  
Author(s):  
Katherine Booker ◽  
Michael C. Bowyer ◽  
Chris J. Lennard ◽  
Clovia I. Holdsworth ◽  
Adam McCluskey
Keyword(s):  
Low Temperature ◽  
Molecularly Imprinted Polymers ◽  
Reaction Times ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Volatile Organic Carbon ◽  
Aconitic Acid ◽  
Significant Acceleration ◽  
Microscopy Examination ◽  
Better Than

Molecularly imprinted polymers (MIPs) were generated for trans-aconitic acid 1 and cocaine 2 in a variety of porogens (CH3CN, CHCl3, [bmim][BF4], and [bmim][PF6]). MIP synthesis in either [bmim][BF4] or [bmim][PF6] resulted in significant acceleration of polymerization rates and, in the case of low temperature polymerizations, reactions were complete in less than 2 h, while no product was observed in the corresponding volatile organic carbon (VOC) porogen. In all instances, MIPs generated in [bmim][BF4] or [bmim][PF6] returned imprinting selectivities (I values) on par with or better than the corresponding MIP generated in VOCs. Imprinting values ranged between I = 1 and 2.9, with rebinding limited to 1 h. MIP synthesis conducted at low temperature (5°C) afforded the highest I values. Scanning electron microscopy examination of MIP morphology highlighted an unexpected template effect with MIP structure varying between discrete nanoparticles and robust monoliths. This template–monomer interaction was also observed in the rates of polymerizations with differences noted in reaction times for 1 and 2 MIPs, thus providing indirect conformation of our previously proposed use of molecular modelling–nuclear magnetic resonance titrations (the MM-NMR method) in the design phase of MIP generation. In addition, considerable batch-to-batch rebinding selectivities were observed.

scholarly journals PICKLING EXPERIMENTAL STUDY ON PREPARATION OF DIESEL OIL WITH PYROLYSIS OIL FROM WASTE RUBBER

2017 ◽  
Vol 1 ◽  
pp. 169
Author(s):  
Wang Lei ◽  
Wang Yun ◽  
Jin Jie
Keyword(s):  
Experimental Study ◽  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Diesel Oil ◽  
Pyrolysis Oil ◽  
Waste Rubber ◽  
Pickling Process ◽  
Concentrated Sulfuric Acid ◽  
Better Than

The research has been done for removing asphaltene by pickling process of diesel oil from pyrolysis oil self-made by waste rubber in this paper, and the study showed that pickling effect of concentrated sulfuric acid was better than concentrated hydrochloric acid. The best pickling effect was found when the concentration of sulfuric acid was 18.4mol/L, acid to oil ratio, namely, the amount of concentration of sulfuric acid to the amount of diesel oil ratio, was 25%. This experiment proved that removing asphaltene by pickling process using concentrated sulfuric acid was remarkable.

Long-Chain Branching and Mechanism Controlling Molecular Weight in Hevea Rubber

1999 ◽  
Vol 72 (4) ◽  
pp. 712-720 ◽  
Author(s):  
Jitladda Tangpakdee Sakdapipanich ◽  
Tippawan Kowitteerawut ◽  
Krisda Suchiva ◽  
Yasuyuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Branch Points ◽  
Long Chain Branching ◽  
Linear Character ◽  
Close Relationship ◽  
Deproteinized Natural Rubber ◽  
Long Chain

Abstract The linear character of transesterified deproteinized natural rubber (DPNR-TE) was confirmed by the analysis of terminal groups with NMR and viscometric analyses. The branch content of DPNR rubber from fresh latex was found to range from 0.3 to 1.3 and 0.7 to 3.2, based on tri- and tetra-functionalities, respectively. The plot between the number of branch-points and molecular weight (MW) can be divided into three fractions: (A) the rubber fractions in MW ranging from 2.4×105 to 1.9×106; (B) between 1.9×105 and 2.4×105; and (C) those of MW less than 1.9×105. The fraction (A) showed the number of branch-points per a branched molecule (m) higher than that of fractions (B) and (C). This plot is superimposable with the bimodal molecular-weight distribution (MWD) of Hevea rubber, showing a good coinciding of peak-tops at the high and low MW fractions. It seems likely that there is a close relationship between the number of branch-point and bimodal MWD of natural rubber.

Thermal and Thermo-Oxidative Degradations of Deproteinized Natural Rubber and Natural Rubber

2011 ◽  
Vol 306-307 ◽  
pp. 50-57 ◽  
Author(s):  
Can Zhong He ◽  
Zheng Peng ◽  
Jie Ping Zhong ◽  
Shuang Quan Liao ◽  
Xiao Dong She ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Natural Rubber ◽  
Oxidative Stability ◽  
Natural Rubber Latex ◽  
Oxidative Degradation ◽  
Decomposition Reaction ◽  
Nitrogen Atmosphere ◽  
Degradation Temperature ◽  
Air Atmosphere ◽  
Deproteinized Natural Rubber

Deproteinization of natural rubber was achieved in the latex stage. The structure of deproteinized natural rubber (DPNR) was characterized by fourier transform infrared spectroscopy (FTIR). The thermo degradation of DPNR was studied by thermogravimetry analysis (TG) under air atmosphere and nitrogen atmosphere. The kinetic parameters apparent activation energies (Ea) of the thermal decomposition reaction been calculated from the TG curves using the method described by Broido. And the results were compared with the thermo degradation of natural rubber (NR) under the same conditions. The effect of proteins in natural rubber latex on thermal/ thermo-oxidative stability of NR was discussed. The results show that: the absorptions of the proteins in DPNR at 1546 ㎝-1, compared to NR, become significantly weaker, nearly disappear, which indicates most of proteins has been removed from NR. The thermo degradation of DPNR in nitrogen atmosphere is a one-step reaction. The initial degradation temperature (T0) 、the maximum degradation temperature（Tp） and the final degradation temperature（Tf）as well as the Ea of DPNR are higher than those of NR, which indicates that DPNR represents a better thermal stability than NR under nitrogen atmosphere. Thermo-oxidative degradation of DPNR and NR are two-step reaction. The characteristic temperatures (T0, Tp and Tf) of DPNR are lower than those of NR. The Ea during the First Step of Thermooxidative Degradation of DPNR are also lower than those of NR. These results prove that the thermo-oxidative stability of DPNR is worse than that of NR. Protein is the key role to the thermal stability of natural rubber.

Preparation, Characterization and UV Absorption of Phosphotungstic Acid Cerium

2014 ◽  
Vol 1061-1062 ◽  
pp. 328-332
Author(s):  
Hai Lian Yu ◽  
Zhen Hu
Keyword(s):  
Phosphotungstic Acid ◽  
Absorption Capacity ◽  
Uv Absorption ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Good Thermal Stability ◽  
Infrared Spectrometer ◽  
The Fourier Transform ◽  
Fluorescence Spectrometer

Phosphotungstic acid cerium [CePW12O40] was prepared with phosphotungstic acid and hydrate cerium nitrate by precipitation method. The Fourier transform infrared spectrometer, X-ray diffractometer, X-ray fluorescence spectrometer and thermal gravimetric analysis were used to characterize product, The UV-VIS spectrophotometer was used to measure its absorption capacity. The results showed that the prepared product is CePW12O40, it has good crystal and good thermal stability, its purity reaches 99.55%, there is good UV absorption property between 200nm and 260nm..

Study on Dehydration Process of Wet Natural Rubber by Single Screw Dehydrator and Properties of Dry Natural Rubber

2011 ◽  
Vol 418-420 ◽  
pp. 544-547
Author(s):  
Mei Chen ◽  
Fu Quan Zhang ◽  
Yong Zhou Wang ◽  
Mao Fang Huang ◽  
Wei Yong Deng
Keyword(s):  
Natural Rubber ◽  
Thermal Oxidation ◽  
Hammer Mill ◽  
Dehydration Process ◽  
Hot Air Drying ◽  
Single Screw ◽  
Hot Air ◽  
Unit Value ◽  
Better Than ◽  
Dehydration Effect

In this work, one self-invented closed single screw dehydrator was used to dehydrate wet natural rubber, instead of current three opened crepers and one hammer mill at home and abroad. The dehydration technology and the properties of the obtained dry natural rubber were studied. The results show that single screw dehydrator can simplify dehydration process. The water consumption of single screw dehydrator is 20% of current productive technology, meaning a lower wastewater discharge and treatment cost of wastewater. The moisture content of dehydrated natural rubber is lower than 20%, a good dehydration effect. The dry natural rubber dehydrated with single screw dehydrator has an improved thermal-oxidation ageing resistance whether dried by hot-air or microwave. The thermal-oxidation ageing resistance of natural rubber dried by microwave is better than that of hot-air drying, the value of initial plasticity (P0) and plasticity retention index (PRI) are 29.3 unit value and 19.26 unit value greater than that of SCR5 in GB/T 8081, respectively.

scholarly journals N-Formylation of Anilines with Silica Sulfuric Acid under Solvent-Free Conditions

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Davood Habibi ◽  
Payam Rahmani ◽  
Ziba Akbaripanah
Keyword(s):  
Sulfuric Acid ◽  
Formic Acid ◽  
Reaction Times ◽  
Solvent Free ◽  
Secondary Amines ◽  
Silica Sulfuric Acid ◽  
Excellent Yield ◽  
Solvent Free Conditions ◽  
Primary And Secondary Amines

N-formylation of primary and secondary amines was carried out with formic acid in the presence of silica sulfuric acid under solvent-free conditions to give the corresponding formamides in excellent yield and short reaction times.

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