Secondary Softening Regions of Copolymers, Mixed Polymers, and Graft Polymers

1957 ◽  
Vol 30 (1) ◽  
pp. 200-214 ◽  
Author(s):  
R. Ecker
Keyword(s):  
Graft Polymers ◽  
Macromolecular Substance ◽  
Schematic Form

Abstract A polymer is a macromolecular substance which is built up from individual monomeric units by a process of chemical linking into a long chainlike substance. Figure 1 is an attempt to give in schematic form a picture of the general structures of three purported types of copolymers, mixed polymers, and graft polymers.

scholarly journals Radiation-Induced Asymmetric Grafting of Different Monomers into Base Films to Prepare Novel Bipolar Membranes

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2028
Author(s):  
Shin-ichi Sawada ◽  
Yasunari Maekawa
Keyword(s):  
Acrylic Acid ◽  
Anion Exchange ◽  
Graft Polymerization ◽  
The Other ◽  
Practical Applications ◽  
Bipolar Membranes ◽  
Graft Polymers ◽  
Grafting Reactions ◽  
Radiation Induced

We prepared novel bipolar membranes (BPMs) consisting of cation and anion exchange layers (CEL and AEL) using radiation-induced asymmetric graft polymerization (RIAGP). In this technique, graft polymers containing cation and anion exchange groups were introduced into a base film from each side. To create a clear CEL/AEL boundary, grafting reactions were performed from each surface side using two graft monomer solutions, which are immiscible in each other. Sodium p-styrenesulfonate (SSS) and acrylic acid (AA) in water were co-grafted from one side of the base ethylene-co-tetrafluoroethylene film, and chloromethyl styrene (CMS) in xylene was simultaneously grafted from the other side, and then the CMS units were quaternized to afford a BPM. The distinct SSS + AA- and CMS-grafted layers were formed owing to the immiscibility of hydrophilic SSS + AA and hydrophobic CMS monomer solutions. This is the first BPM with a clear CEL/AEL boundary prepared by RIAGP. However, in this BPM, the CEL was considerably thinner than the AEL, which may be a problem in practical applications. Then, by using different starting times of the first SSS+AA and second CMS grafting reactions, the CEL and AEL thicknesses was found to be controlled in RIAGP.

Graft Polymers Derived from Natural Rubber

1956 ◽  
Vol 29 (1) ◽  
pp. 99-105 ◽  
Author(s):  
G. F. Bloomfield ◽  
F. M. Merrett ◽  
F. J. Popham ◽  
P. Mc L. Swift
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Transfer Reaction ◽  
Polymer Chains ◽  
Vinyl Monomers ◽  
Grafted Polymer ◽  
Polymeric Chains ◽  
Graft Polymers ◽  
Direct Growth

Abstract Graft polymers result when vinyl monomers are polymerized in the presence of natural rubber, either in solution or as latex, and some of the polymeric chains become attached to the rubber molecules. The properties of the natural rubber can be widely modified according to the nature and the amount of the grafted polymer. The polymer-modified natural rubber appears to be produced by direct growth of polymer chains on to rubber molecules rather than by a transfer reaction involving the rubber. Graft polymers of styrene and methyl methacrylate with natural rubber can be compounded and cured to give light-colored articles of good tensile strength, and rubber-methyl methacrylate graft polymers have outstanding flex-cracking and fatigue resistance.

Characterization of graft polymers

1956 ◽  
Vol 20 (95) ◽  
pp. 317-326 ◽  
Author(s):  
Joseph A. Blanchette ◽  
Lawrence E. Nielsen
Keyword(s):  
Graft Polymers

Production and properties of graft polymers of polyamide fibres with polyisoprene

1976 ◽  
Vol 7 (2) ◽  
pp. 131-134
Author(s):  
N. P. Lits ◽  
T. V. Druzhinina
Keyword(s):  
Graft Polymers

Antibacterial coating of titanium-doped hydroxyapatite nanoparticles on a polymer substrate

2021 ◽  
pp. 2151014
Author(s):  
Masatoshi Okazaki ◽  
Yoshinao Azuma ◽  
Mitsunobu Iwasaki ◽  
Tsutomu Furuzono
Keyword(s):  
Antibacterial Activity ◽  
Positive Control ◽  
Survival Ratio ◽  
Hydroxyapatite Nanoparticles ◽  
Coated Substrate ◽  
Graft Polymers ◽  
Ti Substitution ◽  
Negative Controls ◽  
Sintering Method ◽  
Pet Substrate

Calcined and dispersible titanium-doped hydroxyapatite (Ti-HAp) nanoparticles at different [Ti/(Ca+Ti)] atomic ratios (0.3, 0.4, and 0.5) were prepared using an anti-sintering method. The Ti substitution ratios of the HAp structures in the feed of Ti-HAp preparation were approximately 80%. Ti-HAp nanoparticles were coated on polyethylene terephthalate (PET) sheets through polyacrylic acid graft-polymers. The PET substrate was almost completely covered with monolayer nanoparticles (over 95%). Antibacterial activity of coated Ti-HAp was calculated from the survival ratio of the bacteria, Staphylococcus aureus, after ultraviolet (UV) irradiation at 312 nm and 6.4 mW/cm2 for 30 s. The number of S. aureus on the Ti-HAp coated substrate decreased by 43% compared to those on the original PET and normal HAp coatings as negative controls. The antibacterial activity of Ti-HAp coated substrate was, furthermore, no statistically difference with TiO2 sheet as a positive control.

Education and Transformation in Tanzania

1981 ◽  
Vol 11 (3-4) ◽  
pp. 22-26
Author(s):  
Joel Samoff
Keyword(s):  
Educational Reform ◽  
Social Services ◽  
Southern Africa ◽  
Educational System ◽  
Colonial Rule ◽  
The Public ◽  
Almost Everywhere ◽  
Skilled Personnel ◽  
Insight Into ◽  
Schematic Form

Note: Since this brief review of educational reform in Tanzania is intended to offer insight into a number of problems that confront those involved in transforming the recently independent societies of southern Africa, and since my research on these issues is still at a preliminary stage, I present my comments in schematic form. A brief note on resources and selected citations appear at the end.At the end of colonial rule in Africa, almost everywhere the formal educational system was assigned major roles in the construction of the new society. Skilled personnel had to be trained to replace the departing Europeans. The vast expansion of social services required many new doctors, engineers, and architects. The increased responsibilities of the public sector required managers, accountants, and planners. And, of course, there had to be a rapid increase in the teaching corps, at all levels.

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