Block and Graft Copolymers of Pivalolactone. I. A New Class of Elastoplastics and Thermoplastic Elastomers

1976 ◽  
Vol 9 (2) ◽  
pp. 371-373 ◽  
Author(s):  
S. A. Sundet ◽  
R. C. Thamm ◽  
J. M. Meyer ◽  
W. H. Buck ◽  
S. W. Caywood ◽  
...  
Keyword(s):  
Graft Copolymers ◽  
Thermoplastic Elastomers ◽  
New Class

Cellulose graft copolymers toward strong thermoplastic elastomers via RAFT polymerization

2019 ◽  
Vol 480 ◽  
pp. 162-171 ◽  
Author(s):  
Feng Jiang ◽  
Chenqian Pan ◽  
Yaqiong Zhang ◽  
Yanxiong Fang
Keyword(s):  
Raft Polymerization ◽  
Graft Copolymers ◽  
Thermoplastic Elastomers

Graft Polyrotaxanes: A New Class of Graft Copolymers with Mobile Graft Chains

2011 ◽  
Vol 50 (44) ◽  
pp. 10417-10420 ◽  
Author(s):  
Yasuhiro Kohsaka ◽  
Yasuhito Koyama ◽  
Toshikazu Takata
Keyword(s):  
Graft Copolymers ◽  
New Class

New Thermoplastic Elastomers. Styrene Grafts on Lithiated Polydienes and Their Hydrogenated Counterparts

1973 ◽  
Vol 46 (4) ◽  
pp. 1044-1054 ◽  
Author(s):  
J. C. Falk ◽  
R. J. Schlott ◽  
D. F. Hoeg ◽  
J. F. Pendleton
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Room Temperature ◽  
Graft Copolymers ◽  
Gel Permeation Chromatography ◽  
Thermoplastic Elastomers ◽  
Proper Choice ◽  
Melt Flow ◽  
Gel Permeation ◽  
Poly Ethylene

Abstract Metalation of diene polymers such as poly (butadiene) and poly(isoprene) with sec-butyllithium and tetramethylethylenediamine in cyclohexane at room temperature forms lithiated polydienes. Reaction of the polylithiodienes with styrene or α-methylstyrene forms graft copolymers. The extent of metalation is much greater than previously reported metalations with n-butyllithium and tetramethylethylenediamine. The grafting efficiencies, determined by acetone extraction and gel permeation chromatography, are greater than 95 per cent. Graft copolymers of poly (styrene) on EPDM rubbers may also be prepared using this technique. The physical properties of the graft copolymers are a function of molecular weight, graft site level, and composition. Products at specific compositions and graft levels are thermoplastic elastomers. Their properties are comparable to SBS rubbers, and offer as an advantage high melt flow. Graft copolymers of poly(styrene) on poly(ethylene) and poly(ethylene-co-butene-1) result from the hydrogenation of the butadiene moeities of graft copolymers of poly (styrene) on 1,4-poly(butadiene) and 1,2 and 1,4-butadiene copolymers, respectively. Complete hydrogenation results in graft copolymers of poly(vinylcyclohexane) on poly(ethylene) and on poly(ethylene-co-butene-1). In both of these cases thermoplastic elastomers result if the proper choice of composition and graft level is made.

Graft Polyrotaxanes: A New Class of Graft Copolymers with Mobile Graft Chains

2011 ◽  
Vol 123 (44) ◽  
pp. 10601-10604 ◽  
Author(s):  
Yasuhiro Kohsaka ◽  
Yasuhito Koyama ◽  
Toshikazu Takata
Keyword(s):  
Graft Copolymers ◽  
New Class

International Rubber Science Hall of Fame Inductee

2008 ◽  
Vol 81 (2) ◽  
pp. 1-6
Author(s):  
Geoff Holden
Keyword(s):  
Anionic Polymerization ◽  
Graft Copolymers ◽  
Polymeric Materials ◽  
Thermoplastic Elastomer ◽  
Polymer Science ◽  
Living Anionic Polymerization ◽  
New Class ◽  
Vulcanized Rubber ◽  
Hall Of Fame ◽  
American Scientist

Abstract Citation* - American scientist, chemist. Dr. Ralph Milkovich was a pioneer in anionic polymerization and heterophase polymer science. He demonstrated the concept of living anionic polymerization. He prepared the first poly(styrene-block-isoprene-block-styrene) thermoplastic elastomer, exhibiting the properties of a vulcanized rubber but processible as a thermoplastic. He also prepared a new class of polymeric materials, macromonomers, useful for the syntheses of well-defined, comb-type graft copolymers.

Polystyrene-immobilized poly(ethylene imine) chains ? a new class of graft copolymers

1996 ◽  
Vol 37 (5) ◽  
pp. 565-572 ◽  
Author(s):  
E. Bayer ◽  
X. N. Liu ◽  
U. Tallarek ◽  
A. Ellwanger ◽  
K. Albert ◽  
...  
Keyword(s):  
Graft Copolymers ◽  
Ethylene Imine ◽  
New Class ◽  
Poly Ethylene

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

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