Synergistic effect of PLA–PBAT–PLA tri-block copolymers with two molecular weights as compatibilizers on the mechanical and rheological properties of PLA/PBAT blends

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73842-73849 ◽  
Author(s):  
Zhiqiang Sun ◽  
Bao Zhang ◽  
Xinchao Bian ◽  
Lidong Feng ◽  
Han Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Synergistic Effect ◽  
Rheological Properties ◽  
Systematic Study ◽  
Synergistic Effects ◽  
Molecular Weights ◽  
Different Molecular Weight

Systematic study on the synergistic effects of different molecular-weight PLA–PBAT–PLA tri-block copolymers on the mechanical and rheological properties of PLA/PBAT blends.

Effect of Different Molecular Weight of PEG on the Crystallization Behaviors of Binary Polymer Blends PLA/TPS

2021 ◽  
Vol 1035 ◽  
pp. 918-924
Author(s):  
Teng Zhang ◽  
Su Mei Zheng
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Flow Rate ◽  
Crystallization Rate ◽  
Thermoplastic Starch ◽  
Extrusion Process ◽  
Poly Lactic Acid ◽  
Melt Flow Rate ◽  
Poly Ethylene ◽  
Different Molecular Weight

Serial poly (lactic acid) (PLA) and thermoplastic starch (TPS) blends (with a fixed content of 20 wt.% TPS) were prepared by melt extrusion process. The effect of different molecular weight of PEG on the thermal and rheological properties of PLA/TPS blends was studied by the melt flow rate (MFR) and DSC analysis. The results showed that the molecular weight of PEG influenced the miscibility and crystallization behavior of PLA/TPS blends. Blend added with PEG400 showed a single Tg, and blends with PEG600 provided remarkable improvement of rheological properties with an increase in flow rate to 49.02 g/10 min. 4% content of poly (ethylene glycol) (PEG) can positively contribute to improve crystallization rate of PLA by reducing the melting temperature and cold crystallization temperature.

scholarly journals Synergistic toughening of polypropylene with ultra-high molecular weight polyethylene and elastomer-olefin block copolymers

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23994-24002 ◽  
Author(s):  
Lucheng Qi ◽  
Lei Wu ◽  
Ren He ◽  
Hui Cheng ◽  
Boping Liu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Rheological Properties ◽  
High Molecular Weight ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Ultra High Molecular Weight

Blends of polypropylene (PP) and ultra-high molecular weight polyethylene (UHMWPE) with elastomer-olefin block copolymers (OBC) were prepared using an ultrasonic twin-screw extruder, and their mechanical and rheological properties were investigated.

Relationships between Molecular Weights and Rheological Properties of Asphalts

1996 ◽  
Vol 1535 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Jan F. B ranthaver ◽  
Raymond E. Robertson ◽  
John J. Duvall
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Molecular Associations ◽  
Weight Distributions ◽  
Exclusion Chromatography ◽  
Microstructural Model

It is known that the rheological properties of mixtures of organic compounds are functions of molecular weight distributions. However, with respect to asphalts, which are composed of many different compounds and compound types, molecular weights are difficult to measure. This difficulty occurs because the molecular associations that form are held together by forces of varying strengths and are partly broken up by heat and solvents. In theory, the strongest molecular associations in asphalts should have the greatest influence on the rheological properties of asphalts. These associations would be expected to be the major contributors to the asphalt's behaving as if it were a relatively high molecular weight material. Asphalt molecular associations should be isolatable by means of size exclusion chromatography. Several fractions of varying molecular weights (measured by membrane osmometry and vapor phase osmometry) were isolated from Strategic Highway Research Program (SHRP) asphalt AAD-1 by preparative size exclusion chromatography. Molecular weights of these fractions ranged from approximately 2,000 daltons to over 40,000 daltons. When these fractions were independently mixed with asphalt AAD-1 solvent moiety, mixtures were obtained whose rheological properties were a function of the molecular weights and concentrations of the associated materials. These results support the microstructural model of asphalt proposed during SHRP. The results also suggest that the unusual rheological properties of some asphalts may be explained by measuring molecular weight distributions. This type of information may be useful for modification of asphalts to achieve desirable rheological properties.

Kinetic study of DNA hybridization on DNA-modified gold nanoparticles with engineered nano-interfaces

RSC Advances ◽  
2015 ◽  
Vol 5 (93) ◽  
pp. 76014-76018 ◽  
Author(s):  
Akari Takashima ◽  
Motoi Oishi
Keyword(s):  
Molecular Weight ◽  
Gold Nanoparticles ◽  
Kinetic Study ◽  
Systematic Study ◽  
Dna Hybridization ◽  
Key Factors ◽  
Different Molecular Weight

We report a systematic study of DNA hybridization kinetics on GNPs with probe DNA and different molecular weight PEGs, and protruding structure of probe DNA from the PEG layer is the key factors for DNA hybridization on GNPs.

scholarly journals On the Dependence of Rheology of Hyaluronic Acid Solutions and Frictional Behavior of Articular Cartilage

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2659 ◽  
Author(s):  
David Rebenda ◽  
Martin Vrbka ◽  
Pavel Čípek ◽  
Evgeniy Toropitsyn ◽  
David Nečas ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Rheological Properties ◽  
Optical Glass ◽  
Clinical Results ◽  
Frictional Behavior ◽  
Molecular Weights ◽  
The Coefficient Of Friction ◽  
Contact Couple

Hyaluronic acid (HA) injections represent one of the most common methods for the treatment of osteoarthritis. However, the clinical results of this method are unambiguous mainly because the mechanism of action has not been clearly clarified yet. Viscosupplementation consists, inter alia, of the improvement of synovial fluid rheological properties by injected solution. The present paper deals with the effect of HA molecular weight on the rheological properties of its solutions and also on friction in the articular cartilage model. Viscosity and viscoelastic properties of HA solutions were analyzed with a rotational rheometer in a cone–plate and plate–plate configuration. In total, four HA solutions with molecular weights between 77 kDa and 2010 kDa were tested. The frictional measurements were realized on a commercial tribometer Bruker UMT TriboLab, while the coefficient of friction (CoF) dependency on time was measured. The contact couple consisted of the articular cartilage pin and the plate made from optical glass. The contact was fully flooded with tested HA solutions. Results showed a strong dependency between HA molecular weight and its rheological properties. However, no clear dependence between HA molecular weight and CoF was revealed from the frictional measurements. This study presents new insight into the dependence between rheological and frictional behavior of the articular cartilage, while such an extensive investigation has not been presented before.

scholarly journals EFFECT OF POLYETHYLENE MOLECULAR MASS CHARACTERISTICS ON SLIP EFFECT

2016 ◽  
Vol 11 (5) ◽  
pp. 91-93
Author(s):  
A. A. Yurkin ◽  
I. D. Simonov-Emelyanov ◽  
P. V. Surikov ◽  
N. L. Shembel
Keyword(s):  
Molecular Weight ◽  
Molecular Mass ◽  
Rheological Properties ◽  
Melt Flow Index ◽  
Flow Index ◽  
Slip Effect ◽  
Melt Flow ◽  
Molecular Weight Characteristics ◽  
Different Temperatures ◽  
Different Molecular Weight

The rheological properties of polyethylene with different molecular weight characteristics were studied. Difference of molecular weight characteristics was found on the basis of melt flow index, and slip effect in the molten polyethylene flow was studied. The presence of slip effect is found in case of flowing polyethylene with a higher molecular weight in contrast to polyethylene with lower molecular weight at different temperatures. Changes of the slip effect parameters upon mixing polyethylenes with very much different molecular weight characteristics were studied.

Rheological properties of liquid crystalline solutions of ethyl celluloses with different molecular weight in m-cresol

1988 ◽  
Vol 35 (2) ◽  
pp. 407-437 ◽  
Author(s):  
Shinichi Suto ◽  
Masahiko Ohshiro ◽  
Wataru Nishibori ◽  
Hisashi Tomita ◽  
Mikio Karasawa
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Liquid Crystalline ◽  
Different Molecular Weight

Novel Thermoplastic Elastomers: Star-Blocks Consisting of Eight Poly(Styrene-b-Isobutylene) Arms Radiating from a Calix[8]Arene Core

1998 ◽  
Vol 71 (4) ◽  
pp. 708-721 ◽  
Author(s):  
Sunny Jacob ◽  
Istvan Majoros ◽  
Joseph P. Kennedy
Keyword(s):  
Nmr Spectroscopy ◽  
Block Copolymers ◽  
Rheological Properties ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
High Strength ◽  
Living Polymerization ◽  
Thermoplastic Elastomers ◽  
Molecular Weights ◽  
Star Block Copolymers

Abstract The first synthesis by a core-first strategy of novel star-block copolymers consisting of eight poly(styrene-b-isobutylene) (PSt-b-PIB) arms radiating from a calix[8]arene core is described. An octafunctional methoxy calix[8]arene derivative was used to initiate the living polymerization of isobutylene (IB) to desirable molecular weights, then styrene (St) was added to obtain the sought star-blocks. Molecular weights and PSt contents were determined by triple-detector GPC and 1H NMR spectroscopy. Star-block thermoplastic elastomers containing 17–32% PSt showed high strength and elongation (up to ∼26 MPa and >500%) and relatively low melt viscosities. The mechanical and rheological properties of these star-blocks are superior to those of linear PSt-b-PIB-b-PSt triblocks. PIB-based thermoplastic elastomers may be of use as novel biomaterials.

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