Synthesis of Radial Thermoplastic Elastomers

1976 ◽  
Vol 49 (5) ◽  
pp. 1305-1310 ◽  
Author(s):  
H. L. Hsieh
Keyword(s):  
Coupling Reaction ◽  
Shear Resistance ◽  
Thermoplastic Elastomers ◽  
Lower Solution ◽  
Commercial Production ◽  
Linear Polymers ◽  
Block Sequence ◽  
Block Polymers ◽  
Molecular Weights ◽  
Number Of Branches

Abstract The combination of anionic polymerization techniques and a subsequent coupling reaction created a versatile process for producing block polymers of not only controlled block length and block sequence but also with a controlled number of branches. This process has been successfully used in commercial production since 1967. Radial styrene-diene block polymers have properties significantly different from linear polymers of the same molecular weight, showing lower melt viscosities as well as lower solution viscosities. This feature is significant in adhesive applications because it allows the use of polymers of higher molecular weights with a corresponding improvement in shear resistance.

Preparation of graft copolymers by the reaction of polymeric acyl chlorides with monohydroxy-terminated polymers: An introductory study

1988 ◽  
Vol 53 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Jitka Horská ◽  
Jaroslav Stejskal ◽  
Pavel Kratochvíl ◽  
Aubrey D. Jenkins ◽  
Eugenia Tsartolia ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Statistical Model ◽  
Graft Copolymers ◽  
Coupling Reaction ◽  
Molecular Characteristics ◽  
Gel Formation ◽  
Acyl Chlorides ◽  
Molecular Weights

An attempt was made to prepare well-defined graft copolymers by the coupling reaction between acyl chloride groups located along the backbone chain and monohydroxy-terminated grafts prepared separately. The molecular weights and the parameters of heterogeneity in chemical composition of the products were determined by light scattering and osmometry. The determination of molecular characteristics revealed that the degree of grafting was low. The results therefore could not be confronted with a statistical model at this stage. The problems encountered in the synthesis, e.g., gel formation, and the data relating to the soluble products are discussed.

Structure of Polybutadienes

1967 ◽  
Vol 40 (5) ◽  
pp. 1529-1543 ◽  
Author(s):  
W. S. Bahary ◽  
D. I. Sapper
Keyword(s):  
Light Scattering ◽  
Molecular Size ◽  
Structural Features ◽  
Melting Point Depression ◽  
Linear Polymers ◽  
Long Chain Branching ◽  
Molecular Weights ◽  
Catalyst Systems ◽  
Molecular Size Distribution

Abstract Polybutadienes made with six different catalyst systems were examined: (1) butyllithium, (2) “nickel-based”, (3) alfin, (4) “titanium-based”, (5) “cobalt-based”, and (6) free radical emulsion. The microstructure and macrostructure of the polybutadienes have been determined and are compared to the results published in the literature. These polybutadienes may be considered to be random terpolymers of cis, trans, and vinyl addition of butadiene. The glass transition temperature is specified by the vinyl content. The crystalline melting points of the high trans and also the high cis polybutadienes obey to a high measure Flory's equation for melting point depression of a random terpolymer. The molecular weights of the polybutadienes have been determined by light scattering and osmometry and the degree of long chain branching has been determined by the branching index, 〈g′〉. The macro-structural features of the linear polymers are confirmed by fractionation. However, the polydispersities calculated from fractionation data do not agree with those determined from light scattering and osmometry for the branched samples. The discrepancy is attributed to the method of characterization of the fractions. A distinction is made between molecular weight distribution and molecular size distribution.

scholarly journals Dynamic Dilution Effect in Binary Blends of Linear Polymers with Well-Separated Molecular Weights

2014 ◽  
Vol 47 (21) ◽  
pp. 7653-7665 ◽  
Author(s):  
E. van Ruymbeke ◽  
V. Shchetnikava ◽  
Y. Matsumiya ◽  
H. Watanabe
Keyword(s):  
Dilution Effect ◽  
Linear Polymers ◽  
Binary Blends ◽  
Molecular Weights

Synthesis and Characterization of Linear Polymers for Non-Linear Optics through Click Chemistry Route

2012 ◽  
Vol 584 ◽  
pp. 8-12 ◽  
Author(s):  
Balakrishna Kolli ◽  
Sarada P. Mishra ◽  
Mukesh P. Joshi ◽  
S. Raj Mohan ◽  
T.S. Dhami ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Second Harmonic ◽  
Gel Permeation Chromatography ◽  
Linear Polymers ◽  
Linear Optics ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Molecular Weights ◽  
Non Linear Optics ◽  
Atomic Force

Click chemistry is used for synthesizing polymers for second order NLO study. The molecular weights found by gel-permeation chromatography (GPC), were in the range of 7000-55000 g/mol. Differential scanning calorimetry shows glass transition temperature (Tg) above 120 oC. From electronic spectra order parameter of the poled films were calculated to be 0.1-0.5. The change in surface morphology after poling was checked by atomic force microscopy. By using a pulsed Nd:YAG laser (1064nm), the second harmonic generation (SHG) intensity was measured. The SHG intensity was also studied as a function of against temperature and time respectively.

Angular Distribution of Intensity of Rayleigh Scattering from Comblike Branched Molecules

1968 ◽  
Vol 41 (2) ◽  
pp. 437-451
Author(s):  
Edward F. Casassa ◽  
Guy C. Berry
Keyword(s):  
Angular Distribution ◽  
Rayleigh Scattering ◽  
Large Fraction ◽  
Limited Range ◽  
Radius Of Gyration ◽  
Molecular Weights ◽  
Vinyl Polymers ◽  
Linear Chains ◽  
Angular Distribution Function ◽  
Number Of Branches

Abstract The angular distribution function P(θ) for intensity of light scattered by a dilute solution of comblike branched molecules has been determined for three situations of some interest for evaluation of experimental data: (1) the molecules are identical with branches of equal length attached equidistantly along linear backbone chains; (2) the molecules are homogeneous in mass, with the same number of branches on each molecule, but the branches are distributed at random along the chain; (3) branches and main chains are still uniform, but the molecules are heterogeneous in mass with the number of branches per molecule distributed according to the binomial distribution and the branches in any molecule spaced randomly along the backbone. Examination of numerical results shows that the scattering functions for models (1) and (2) arc not very different. The function for case (3) is somewhat different from the others when the mean number of branches per molecule is small but they contain a large fraction of the mass of the molecule. Over a limited range of the pertinent variables (corresponding roughly to observations on typical vinyl polymers of molecular weights up to 106) all three functions agree quite well with P(θ) for homogeneous linear chains with the same mean square radius of gyration.

scholarly journals Heterogeneous Double Metal Cyanide Catalyzed Synthesis of Poly(ε-caprolactone) Polyols for the Preparation of Thermoplastic Elastomers

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1033
Author(s):  
Chinh-Hoang Tran ◽  
Min-Woong Lee ◽  
Sang-Woo Park ◽  
Jae-Eon Jeong ◽  
Soo-Jeong Lee ◽  
...  
Keyword(s):  
Kinetic Studies ◽  
Thermoplastic Elastomers ◽  
Stress And Strain ◽  
Polypropylene Glycol ◽  
Telechelic Polymers ◽  
One Pot ◽  
Coordination Polymerization ◽  
Free Ring ◽  
Molecular Weights ◽  
Metal Cyanide

A series of polycaprolactones (PCLs) with molecular weights of 950–10,100 g mol−1 and Ð of 1.10–1.87 have been synthesized via one-pot, solvent-free ring-opening polymerization (ROP) of ε-caprolactone (CL) using a heterogeneous double metal cyanide (DMC) catalyst. Various initiators, such as polypropylene glycol, ethylene glycol, propylene glycol, glycerol, and sorbitol, are employed to tune the number of hydroxyl end groups and properties of the resultant PCLs. Kinetic studies indicate that the DMC-catalyzed ROP of CL proceeds via a similar mechanism with the coordination polymerization. Branched PCLs copolymers are also synthesized via the DMC-catalyzed copolymerization of CL with glycidol. The α,ω-hydroxyl functionalized PCLs were successfully used as telechelic polymers to produce thermoplastic poly(ester-ester) and poly(ester-urethane) elastomers with well-balanced stress and strain properties.

Synthesis and characterization of macrocyclic poly(.-methylstyrene)

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Dahai Dong ◽  
Thieo E. Hogen-Esch
Keyword(s):  
Size Exclusion ◽  
Careful Study ◽  
Coupling Reactions ◽  
Linear Polymers ◽  
High Dilution ◽  
Fractional Precipitation ◽  
Molecular Weights ◽  
Vinyl Polymers ◽  
High Concentrations

AbstractThe synthesis is described of macrocyclic poly(α-methylstyrene) (PAMS) by the lithium naphthalide initiated polymerization of AMS followed by high dilution end to end coupling with 1,4-bis(bromomethyl)benzene (DBX). The cyclization is carried out by simultaneous addition of tetrahydrofuran solutions of the PAMS dianion and DBX at about -100ºC. A sample of the matching linear PAMS is obtained by protonation of the PAMS dianion. The purified cycles are obtained by fractional precipitation that is monitored by size exclusion chromatograhy. A careful study of the coupling reactions carried out at high concentrations indicates that coupling is efficient and this is borne out by the ratios (<G>) of apparent molecular weights (MW’s) of cycles and matching linear polymers. The <G> values of the cycles tend to vary with MW in the same manner as was demonstrated for polystyrene and other vinyl polymers and increase from around 0.74 at MW of about 30000 to values of around 0.82 at MW of about 2500. A higher apparent <G> value was observed for a very low MW PAMS but this sample could not be purified and analyzed adequately. As was also observed for other macrocyclic vinylpolymers, the glass transition temperatures of the cycles are MW independent above MW of about 5000 but decrease sharply at lower MW’s.

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