Block Copolymers Poly(2,6-dimethyl-1,4-phenylene oxide)-poly(6-hexanelactam). Preparation and Composition

1993 ◽  
Vol 58 (11) ◽  
pp. 2574-2582 ◽  
Author(s):  
Jaroslav Stehlíček ◽  
Rudolf Puffr
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Diblock Copolymer ◽  
Anionic Polymerization ◽  
Diblock Copolymers ◽  
Toluene Solution ◽  
Low Molecular Weight ◽  
Phenylene Oxide ◽  
End Groups ◽  
Tolylene Diisocyanate

Poly(2,6-dimethyl-1,4-phenylene oxide)-poly(6-hexanelactam) diblock copolymers were prepared from low-molecular weight poly(2,6-dimethyl-1,4-phenylene oxide) by transforming its phenolic end groups via the reaction with 2,4-tolylene diisocyanate and 6-hexanelactam to polymeric initiators and the subsequent anionic polymerization of 6-hexanelactam. The polymerization of 6-hexanelactam was carried out in bulk or toluene solution. The content of the 6-hexanelactam homopolymer was estimated by TLC showing that the pure diblock copolymer can be prepared in toluene. The reason for relatively low yields is discussed.

Mechanical Properties of Blends of Crystallizable Polybutadienes Containing Amorphous Polybutadiene Diblock Copolymers

1994 ◽  
Vol 67 (2) ◽  
pp. 342-347
Author(s):  
Moira Marx Nir ◽  
Robert E. Cohen
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Surface Area ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Tensile Failure ◽  
Interfacial Surface ◽  
Failure Properties ◽  
Enhanced Properties

Abstract Tensile failure properties of syndiotactic 1,2 polybutadiene/trans 1,4 polybutadiene crystalline blends are improved by addition of 5–10% amorphous 1,2 polybutadiene/1,4 polybutadiene diblock copolymer. The effect of block molecular weight and microphase behavior of the diblock copolymer was investigated. Heterogeneous diblocks enhance blend properties to a greater extent than homogeneous diblocks. In blends with enhanced properties, percent coverage of interfacial surface area by diblock is on the order of 10%.

The Ordered Bicontinuous Double Diamond Structure in Binary Blends of Diblock Copolymer and Homopolymer.

1989 ◽  
Vol 171 ◽  
Author(s):  
Karen I. Winey ◽  
Edwin L. Thomas
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Composition Range ◽  
Volume Fraction ◽  
Diamond Structure ◽  
Binary Blends ◽  
Resultant Effect ◽  
Strong Segregation ◽  
Double Diamond

ABSTRACTWe report the observation of the ordered bicontinuous double diamond (OBDD) structure in binary blends of poly(styrene-isoprene) diblock copolymer and homopolystyrene. The overall polystyrene volume fraction range is 64 - 67 PSvol% for the OBDD structure in binary blends of a lamellar diblock (SI 27/22) and a homopolymer (14.0 hPS). This composition range is approximately within the polystyrene volume fraction range established for pure diblock copolymers in the strong segregation regime having the OBDD structure. Ordered lamellae are observed at approximately 65 PSvol% when the homopolystyrene molecular weight is greater than the molecular weight of the polystyrene block of the copolymer. This observation is discussed in terms of the decreased degree of mixing between the homopolymer and the corresponding block and the resultant effect on the interfacial curvature.

Characterization of Sol and Gel in Hevea Natural Rubber

1997 ◽  
Vol 70 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Jitladda Tangpakdee ◽  
Yasukuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Weight Fraction ◽  
Toluene Solution ◽  
Low Molecular Weight ◽  
Branch Points ◽  
Gel Content ◽  
High Ammonia ◽  
Linear Molecules ◽  
Cis And Trans

Abstract The gel content of rubber from high-ammonia latex (HA-latex) decreased significantly after deproteinization with proteolytic enzyme. The addition of 1–2% ethanol in toluene solution reduced the gel content of rubbers from HA-latex, deproteinized HA-latex (HA-DP) and pale crepe. Transesterification of the rubber in toluene solution with sodium methoxide dissolved the gel fraction. The gel fractions solubilized after transesterification showed molecular weight distribution rich in low molecular-weight fraction. The Huggins k′ constant of the fractionated rubbers from solubilized-gels was in the range of 0.42–0.45, lower than that of the fractionated HA-DP of 0.5–0.8. This indicates that all the branch-points were decomposed by transesterification to form linear molecules. The Mn values of rubber chains assembling the gel was 5.5−8.3×105 by 13C-NMR measurements of the ratio between cis- and trans-isoprene units, which were comparable to the molecular weight between crosslinks, Mc, of 7−11×105 by swelling measurements. These findings suggest that the branching and crosslinks are composed of two types of branch-points, i. e. one by association or aggregation of proteins or oligopeptides at the initiating end and the other by ester linkages including phosphoric ester at the terminal end.

scholarly journals A controlled synthesis method of alkyl methacrylate block copolymers via living anionic polymerization at ambient temperature

RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16049-16056 ◽  
Author(s):  
Zheng Li ◽  
Jianding Chen ◽  
Guijin Zou ◽  
Tongyuan Zhang ◽  
Dafu Wei ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Ambient Temperature ◽  
Anionic Polymerization ◽  
Diblock Copolymers ◽  
Synthesis Method ◽  
Controlled Synthesis ◽  
Living Anionic Polymerization ◽  
Alkyl Methacrylate ◽  
High Yields

A series of well-defined diblock copolymers containing PMMA, PEMA and PBMA blocks were synthesized with narrow MWDs and high yields via anionic polymerization, while t-BuOK was selected as initiator in THF at 0 °C. .

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