A Comparative Study of Styrene Polymerization in Deproteinized and Undeproteinized Natural Rubber Latex

2002 ◽  
Vol 75 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Nguyen V. Tho ◽  
Mohd Omar Abd Kadir ◽  
Azanam S. Hashim
Keyword(s):  
Reaction Time ◽  
Natural Rubber ◽  
In Situ Polymerization ◽  
Natural Rubber Latex ◽  
Lipid Layer ◽  
Rubber Latex ◽  
Styrene Polymerization ◽  
High Ammonia ◽  
Deproteinized Natural Rubber

Abstract An investigation on in situ polymerization of styrene in deproteinized natural rubber (DPNR) latex and high ammonia natural rubber (HANR) latex was carried out. The ratio of styrene to dry rubber was fixed at 25 : 75 by weight. It was observed that, at reaction temperature of 60 °C and reaction time of 10 hours, the styrene-DPNR system could attain a high conversion of 97% without adding surfactant. The degree of chemical bonding estimated for the resultant polystyrene-DPNR dried material was about 80%. The styrene-HANR system, however, required the addition of surfactant to complete the reaction time; but the conversion was found to be relatively low, in the region of 66%. This low conversion could be attributed to the role played by the protein/lipid layer, which is virtually absent in the styrene-DPNR system.

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.

Development of latex foam pillows from deproteinized natural rubber latex

2021 ◽  
Author(s):  
Roslim Ramli ◽  
Ai Bao Chai ◽  
Shamsul Kamaruddin ◽  
Jee Hou Ho ◽  
Fatimah Rubaizah Mohd. Rasdi ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Deproteinized Natural Rubber

Novel Method for Preparation of Low Molecular Weight Natural Rubber Latex

1998 ◽  
Vol 71 (4) ◽  
pp. 795-802 ◽  
Author(s):  
Jitladda Tangpakdee ◽  
Megumi Mizokoshi ◽  
Akiko Endo ◽  
Yasuyuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Oxidative Degradation ◽  
Low Molecular Weight ◽  
Rubber Latex ◽  
High Ammonia ◽  
Novel Method ◽  
Η Value ◽  
Telechelic Polymer

Abstract Low molecular-weight natural rubber (LNR) and LNR latex was prepared by oxidative degradation of de-proteinized natural rubber (DPNR) latex in the presence of 1 phr of K2S2O8 and 15 phr of propanal, by shaking at 60 °C. The intrinsic viscosity [η] of DPNR with only K2S2O8 decreased from 7.2 to 5.5 after 2 h and then increased to 6.5 after 3 h. By the addition of propanal, DPNR showed a significant decrease in the [η] value of LNR with [η] of about 0.5 after 5 h of the reaction, while rubber from high-ammonia natural rubber (HANR) latex showed a slight decrease in [η]. The concentration of latex and the kind of surfactant used for stabilizing the latex had little effect on the degradation rate of DPNR latex. The LNR latex is stable as the latex form and the dried rubber coagulated from latex is transparent and colorless. The LNR was a telechelic polymer containing aldehyde and ketone groups at both terminals as determined by NMR and molecular weight analyses.

Deproteinized Natural Rubber as Chewing Gum Base for Nicotine Delivery

2013 ◽  
Vol 844 ◽  
pp. 470-473
Author(s):  
Wiwat Pichayakorn ◽  
Prapaporn Boonme ◽  
Wirach Taweepreda
Keyword(s):  
Natural Rubber ◽  
Room Temperature ◽  
Natural Rubber Latex ◽  
Sodium Carboxymethylcellulose ◽  
Rubber Latex ◽  
Initial Modulus ◽  
Chewing Gums ◽  
Significant Difference ◽  
Saccharin Sodium ◽  
Deproteinized Natural Rubber

This study aimed to prepare the nicotine chewing gums for smoking cessation using deproteinized natural rubber latex (DNRL) as gum bases due to its highly flexible property. The formulations were produced by the conventional heat melting and kneading methods. The experimental design was used to obtain the optimum 3 gum base formulations. Each formulation composed of olive oil as a plasticizer; sodium carboxymethylcellulose as an adsorbent; xylitol, mannitol and saccharin sodium as sweeteners instead of sugar. Gum base 1 and gum base 2 had the same sweetener amount but gum base 2 had the lower plasticizer amount, while gum base 1 and gum base 3 had the same plasticizer amount but different sweetener amount. Nicotine was added into each 3 gum bases (NCT1-3). The results showed no significant difference of appearance and taste. Their physicochemical properties were as following: pH of 8.45, 8.46, 8.54, hardness of 39.80, 36.28, 33.14 Shore A, initial modulus of 0.090, 1.260, 0.065 MPa, %elongation of 286, 403, 489%, drug content of 63.62, 70.95, 72.70%, and drug release when 500 times for force clamping of 48.72, 45.72, 67.74%, respectively. After storage at room temperature for 1 month, NCT1 and NCT2 showed unchangeable appearance, but NCT3 showed the slightly liquefied film and much sticky due to hygroscopic property of its sweetener. However, all formulations showed the significant reduction of drug amount which should be further improved in their stability properties.

Morphology of peroxide-prevulcanised natural rubber latex: effect of reaction time and deproteinisation

2003 ◽  
Vol 282 (2) ◽  
pp. 177-181 ◽  
Author(s):  
P. Tangboriboonrat ◽  
D. Polpanich ◽  
T. Suteewong ◽  
K. Sanguansap ◽  
U. Paiphansiri ◽  
...  
Keyword(s):  
Reaction Time ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Latex

CHLORINATION REACTION KINETICS OF THE LOW-CONCENTRATION NATURAL RUBBER LATEX

2013 ◽  
Vol 86 (4) ◽  
pp. 604-614 ◽  
Author(s):  
Lanzhen He ◽  
Jieping Zhong ◽  
Jing Chen ◽  
Chenpen Li ◽  
Linxue Kong ◽  
...  
Keyword(s):  
Reaction Time ◽  
Natural Rubber ◽  
Reaction Temperature ◽  
High Speed ◽  
Kinetic Constant ◽  
Natural Rubber Latex ◽  
Chlorination Reaction ◽  
Rubber Latex ◽  
Low Concentration ◽  
Kinetics Of

ABSTRACT The kinetics of the chlorination of low-concentration natural rubber latex was investigated. The kinetic data were derived from chlorine concentrations in chlorinated natural rubber (CNR) for different reaction times and temperatures. The chlorination reaction process can be divided into two stages—a high-speed period (stage 1) and a low-speed period (stage 2)—using the graphed curves of the change in chlorine content with change in reaction time. The relationship of the chlorination conversion ratio x to reaction time t and temperature T can be expressed as x = 1.15 − 0.916e−kt, where the kinetic constant k = 0.00907 + 6.39 × 10−6e0.0211T. The overall apparent reaction order n for the first stage is 4.8, whereas for the second stage it is 1.0, using kinetic fitting. The apparent activation energy Ea was calculated, using the Arrhenius equation, to be 5.32 kJ/mol for stage 2. The lower value of Ea suggests that the chlorination rate is less sensitive to reaction temperature in this stage. The chlorination reaction rate increases with the increase in reaction temperature during stage 2, but the effects are not visible. However, a temperature that is too high may result in energy being wasted. We conclude that the proper reaction temperature in stage 2, taking the kinetic effects into account, is between 323.15 and 353.15 K.

EFFECT OF DECELERATED FERMENTATION ON MORPHOLOGY AND MECHANICAL PROPERTIES OF NATURAL RUBBER LATEX

2013 ◽  
Vol 86 (4) ◽  
pp. 615-625 ◽  
Author(s):  
Oraphin Chaikumpollert ◽  
Osamu Wakisaka ◽  
Akio Mase ◽  
Yoshimasa Yamamoto ◽  
Krisda Suchiva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Scanning Probe Microscopy ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Gel Content ◽  
High Ammonia ◽  
The Relationship ◽  
Nanomatrix Structure ◽  
Morphology And Mechanical Properties

ABSTRACT Decelerated fermentation of natural rubber latex was performed to investigate the relationship between the morphology and mechanical properties of natural rubber. Natural rubber latex was preserved with sodium hydroxymethylglycinate, as a bactericide, to decelerate the fermentation of nonrubber components such as proteins, phospholipids, carbohydrate, and so forth. Gradual increases in the viscosity of the latex and gel content of the resulting rubber took place as the preservation period was prolonged, which were distinguished from less change in the viscosity of high-ammonia natural rubber (HANR) and high gel content of its rubber. The particle size distribution was dramatically changed during decelerated fermentation, although that of the HANR latex did not change. The pH and nitrogen content of the rubbers were independent of the preservation time. Morphology of the fermented natural rubber and the HANR was observed with scanning probe microscopy. Fewer mechanical properties of the fermented natural rubber were related to the destruction of the nanomatrix structure of the nonrubber components, which resulted from the decrease in the fatty acid ester groups with bacteria as compared with the good mechanical properties of the HANR.

ADSORPTION OF WATER-EXTRACTABLE PROTEINS IN NATURAL RUBBER LATEX SERUMS BY POLY(METHYL METHACRYLATE)/POLYETHYLENEIMINE CORE-SHELL NANOPARTICLES

2016 ◽  
Vol 89 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Aditjaya Jivapongvitoon ◽  
Panya Sunintaboon ◽  
Surapich Loykulnant ◽  
Krisda Suchiva
Keyword(s):  
Electron Microscope ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Natural Rubber Latex ◽  
Core Shell ◽  
Rubber Latex ◽  
Shell Nanoparticles ◽  
High Ammonia ◽  
Core Shell Nanoparticles ◽  
Pei Nanoparticles

ABSTRACT Poly(methyl methacrylate)/polyethyleneimine (PMMA/PEI) core-shell nanoparticles were prepared by emulsifier-free emulsion polymerization. Micrographs from a scanning electron microscope and transmission electron microscope displayed their spherical shape with core-shell morphology in which PMMA was a core and PEI was a shell. The PMMA/PEI nanoparticles' ability to adsorb proteins from the serum of commercial low-ammonia preserved fresh field natural rubber latex was illustrated. The driving force for adsorption was proposed to be mainly via electrostatic interaction between the protonated amino groups of PEI chains on the nanoparticles' surface and phospholipids or protein molecules on NR particles. The reduction percentage was about 50%, depending on the content of PMMA/PEI nanoparticles and mixing time. For comparison, the protein reduction performance by the nanoparticles with two additional extracted serums, high-ammonia preserved concentrated NRL and Thai advanced preservative system NRL, which have different initial protein contents and pH values, was also investigated. The preliminary evaluation of PMMA/PEI nanoparticles' performance in sulfur-prevulcanized high-ammonia preserved concentrated NRL was also studied. Its corresponding sheet had lower extractable proteins by 50% and had tensile strength and elongation at break of 25.5 MPa and 715%, respectively.

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