Formation of graft polymers by γ-irradiation of natural rubber latex and methyl methacrylate

1959 ◽  
Vol 39 (135) ◽  
pp. 419-426 ◽  
Author(s):  
E. G. Cockbain ◽  
T. D. Pendle ◽  
D. T. Turner
2021 ◽  
Vol 12 (1) ◽  
pp. 296
Author(s):  
Bahruddin Ibrahim ◽  
Zuchra Helwani ◽  
Ivan Fadhillah ◽  
Arya Wiranata ◽  
Joni Miharyono

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.


2008 ◽  
Vol 47-50 ◽  
pp. 1149-1152 ◽  
Author(s):  
Pranee Chumsamrong ◽  
Jakkarin Mondobyai

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.


1958 ◽  
Vol 31 (3) ◽  
pp. 430-435 ◽  
Author(s):  
B. C. Sekhar

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.


2016 ◽  
Vol 89 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Aditjaya Jivapongvitoon ◽  
Panya Sunintaboon ◽  
Surapich Loykulnant ◽  
Krisda Suchiva

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.


Sign in / Sign up

Export Citation Format

Share Document