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.

scholarly journals Properties of Emulsion Paint with Modified Natural Rubber Latex/Polyvinyl Acetate Blend Binder

2021 ◽  
Vol 12 (1) ◽  
pp. 296
Author(s):  
Bahruddin Ibrahim ◽  
Zuchra Helwani ◽  
Ivan Fadhillah ◽  
Arya Wiranata ◽  
Joni Miharyono
Keyword(s):  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Polyvinyl Acetate ◽  
Natural Rubber Latex ◽  
Binder Content ◽  
Rubber Latex ◽  
Drying Time ◽  
Emulsion Paint ◽  
Grafting Copolymerization ◽  
Direct Use

The direct use of natural rubber latex (NRL) as a binder for emulsion paints did not produce emulsion paints with good opacity, washability resistance, and regulated touch drying time, even when mixed with polyvinyl acetate (PVAc). This study aimed to study the properties of opacity (hiding power), washability resistance, and set drying touch time of emulsion paint with a binder added from a mixture of modified natural rubber latex (NRL) and PVAc. NRL modifications included UV photodepolymerization with TiO2 catalyst and grafting copolymerization of methyl methacrylate and styrene (NRL-g-(MMA-co-St)). NRL was mixed with PVAC at ratios of 0/100; 15/85; 25/75; 35/65; 50/50; 100/0% w/w before being used as a binder for emulsion paint. Emulsion paint samples had different binder contents, namely 2, 4, 6, and 8% w/w. Tests on paint samples included opacity using a UV-Vis spectrophotometer (EASYSPEC safas Monaco), washability using the Digital BGD 526 Wet Abrasion Scrub Tester, and drying time set using the ASTM STP500 procedure. The results showed that the opacity (hiding power), washability resistance, and set drying touch time met the emulsion paint standards for all binder levels, except the 100% w/w modified NRL composition. The higher level of NRL in the binder causes these properties to decrease and become unstable. The best opacity (hidden power), washing resistance, and drying touch time were obtained on modified NRL with a concentration of 15% w/w. The binder content in the paint was around 4% w/w, with an opacity of about 1.78% abs, washing resistance of 12 times, and the set drying touch time to 80 min.

Preparation, Adhesive Performance and Stability of Natural Rubber Latex Grafted with N-Butyl Acrylate (BA) and Methyl Methacrylate (MMA)

2008 ◽  
Vol 47-50 ◽  
pp. 1149-1152 ◽  
Author(s):  
Pranee Chumsamrong ◽  
Jakkarin Mondobyai
Keyword(s):  
Shear Strength ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Butyl Acrylate ◽  
Natural Rubber Latex ◽  
Peel Strength ◽  
Rubber Latex ◽  
Weight Percentage ◽  
Monomer Ratio ◽  
Lap Shear

In order to study the potential of increasing the weather stability of natural rubber latex for use as a water-based contact adhesive, the natural rubber latex was modified by graft copolymerization with n-butyl acrylate (BA) and methyl methacrylate (MMA). The grafting reaction was carried out using emulsion polymerization at 60°C. Potassium persulfate was used to initiate polymerization. Four different weight percentage ratios of BA to MMA used in this work were 80:20, 70:30, 60:40 and 50:50. Percentage conversion of the monomer of all latexes prepared was ≥ 79.8 %. The grafting efficiency of grafted natural rubber latexes with a different monomer ratio tended to decrease with an increase of MMA. The adhesion property was characterized by 90° peel strength and 180° lap shear tests. The shear strength value of grafted natural rubber latexes increased with an increase of MMA content. The grafted latex with the monomer ratio of 50:50 possessed higher shear strength than natural rubber latex. The peel strength value of grafted natural rubber latexes seemed to lower than that of natural rubber latex. The weather stability of the modified latex was characterized using thermogravimetric analysis (TGA) and also the peel samples were left in the open air for 45 days before testing. The results showed that grafted natural rubber latex had a higher weather stability than natural rubber latex.

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.

Aeration of Natural Rubber Latex. II. Graft Polymerization of Vinyl Monomers with Aerated Latex Rubber

1958 ◽  
Vol 31 (3) ◽  
pp. 430-435 ◽  
Author(s):  
B. C. Sekhar
Keyword(s):  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Graft Polymerization ◽  
Natural Rubber Latex ◽  
Gel Strength ◽  
Vinyl Monomers ◽  
Polymer Content ◽  
Rubber Latex ◽  
Film Forming ◽  
Vinyl Polymer

Abstract The peroxidic groups produced on the rubber hydrocarbon when oxygen is absorbed by ammonia-preserved latex are capable of initiating the graft polymerization of methyl methacrylate and other vinyl monomers, in the presence of suitable reducing agents. The products so formed contain only small proportions of unbound homopolymer. In the latex state, the products have a much higher wet gel strength and better film forming properties than materials of the same total vinyl polymer content prepared by other methods.

A Method for Preparing Rubber Latex Specimens for the Electron Microscope

1947 ◽  
Vol 20 (2) ◽  
pp. 602-606 ◽  
Author(s):  
R. H. Kelsey ◽  
E. E. Hanson
Keyword(s):  
Electron Microscope ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Specimen Preparation ◽  
Electron Micrograph ◽  
Glass Capillary ◽  
Rubber Latex ◽  
Latex Particles ◽  
The Individual ◽  
Collodion Film

Abstract The preparation of natural and synthetic rubber latex specimens for examination with an electron microscope is difficult because the individual particles are easily deformed and, under the usual conditions of specimen preparation, the particles tend to agglomerate. Von Ardenne and Beischer and others used a method which consisted of depositing a drop of highly diluted latex on a collodion film and allowing the drop to dry completely. In some instances the drop was withdrawn again into a glass capillary. It was found that in either case the latex particles were flattened at their areas of contact with the collodion film. The collodion film method was tried in this laboratory with the same poor results observed by Hendricks, Wildman, and McMurdee. Figure 1 is an electron micrograph of a natural rubber latex particle deposited by evaporating latex diluted 200 to 1 on a collodion film. The film has broken and curled to give a profile view of the particle which is observed to be badly flattened at its area of contact with the film. Figure 2 is a typical electron micrograph of natural rubber latex particles deposited on a collodion film. The blurred outlines of the particles are explained by the effect shown in Figure 1. It was obviously impossible to make good particle-size measurements from micrographs of this type. It was found further that severe aggregation of particles usually took place when a drop of the diluted latex was dried down. The latex particles which were left behind when the drop was removed with a glass capillary usually were not badly agglomerated, but it was felt that there was some possibility that the latex particles might adhere selectively according to size to the collodion film. An attempt was made to reduce the amount of agglomeration by incorporating in the diluting water various amounts of such wetting or dispersing agents as sodium oleate, orvis paste, Aerosol-OT, and ammonium caseinate. None of these materials helped very much in reducing the agglomeration of particles. It was found also in this study that very often the latex particles appeared granular around their edges due to foreign material being swept in during the evaporation of the water and crystallizing out upon the surface of the particle. This effect may also be observed in Figure 1.

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