Super toughened and highly ductile PLA / TPU blend systems by in situ reactive interfacial compatibilization using multifunctional epoxy‐based chain extender

2021 ◽  
Vol 138 (20) ◽  
pp. 50457 ◽  
Author(s):  
Yusuf Kahraman ◽  
Burcu Özdemir ◽  
Volkan Kılıç ◽  
Yonca Alkan Goksu ◽  
Mohammadreza Nofar
Keyword(s):  
Chain Extender

Synthesis and Characterization of Temperature-Sensitive TSPU/PNIPAAm Semi-IPN Polymer

2011 ◽  
Vol 399-401 ◽  
pp. 359-362 ◽  
Author(s):  
Yi Chun Wang ◽  
Zheng Wei Dai ◽  
Yuan Xue
Keyword(s):  
Chemical Structure ◽  
In Situ Polymerization ◽  
Phenyl Isocyanate ◽  
Chain Extender ◽  
Synthesis And Characterization ◽  
Temperature Sensitive ◽  
Sensitive Material ◽  
Ft Ir

Thermo-sensitive polyurethane (TSPU) was synthesized from poly(ε-caprolactone) and 4,4’-methylenebis (phenyl isocyanate) by a two-step process with 1,4-butanediol as the chain extender. Following that, a novel temperature-sensitive material was created by the strategy of IPN from TSPU and PNIPAAm in the method of in situ polymerization. The chemical structure and thermo properties of the semi-IPN were characterized with FT-IR and DSC. The results prove that intensive inter-molecular interactions exist between TSPU and PNIPAAm chains, which have significant influence on the phase transition behaviors of the material. According to these results, the transition temperature of the semi-IPN can be adjusted in the range of 30~40 °C by controlling the composition of TSPU and the semi-IPNs.

FEATURES OF IN SITU FORMATION OF MIXTURES OF LINEAR POLYMERS

2021 ◽  
Vol 43 (4) ◽  
pp. 280-286
Author(s):  
T.D. IGNATOVA ◽  
◽  
L.F. KOSYANCHUK ◽  
Keyword(s):  
Phase Separation ◽  
Molecular Mass ◽  
Radical Polymerization ◽  
Chemical Nature ◽  
Chain Extender ◽  
Molar Ratio ◽  
Conversion Degree ◽  
Linear Polymers ◽  
A Chain

This article is devoted to the analysis of the results of the investigation of the process of forming mixtures of linear polymers formed simultaneously in situ according to different mechanisms. The first mechanism is polyaddition, the second mechanism is radical polymerization. This is one of the possible ways to obtain multicomponent polymer systems. The kinetics of chemical reactions of the formation of components and the phase separation which accompanies these reactions were studied for mixtures of poly(methyl methacrylate) (PMMA) with two polyurethanes (PU) of different chemical nature of both flexible and rigid blocks. PU-1 was synthesized from macrodiisocyanate based on oligo(tetramethylene glycol) with molecular mass 1000 g·mol–1 and hexamethylene diisocyanate taken in the molar ratio 1 : 2 using diethylene glycol as a chain extender. PU-2 was synthesized from macrodiisocyanate based on olygo(propylene glycol) with molecular mass 1000 g·mol–1 and toluylene diisocyanate taken in the molar ratio 1 : 2 using butanediol as a chain extender. The mixture of polystyrene (PS) with PU-2 was studied too. It is established that regardless of the chemical nature of the components, the process of in situ mixture formation is subject to general laws. In particular, the change in the chemical nature of the component formed by the mechanism of polyaddition (mixtures PMMA/PU-1 and PMMA/PU-2) or of the component formed by radical polymerization (mixtures PMMA/PU-2 and PS/PU-2) does not affect the nature of the dependence of the conversion degree of components and the fraction of formed polymers at the beginning of the phase separation on the composition of the initial reaction mixtures. Only the absolute values of these parameters change due to different reactivity and different thermodynamic compatibility of the mixed components.

Mechanically strong and stretchable polyurethane–urea supramolecular hydrogel using water as an additional in situ chain extender

RSC Advances ◽  
2014 ◽  
Vol 4 (46) ◽  
pp. 24095-24102 ◽  
Author(s):  
Chao Deng ◽  
Yulin Cui ◽  
Tingting Zhao ◽  
Mei Tan ◽  
He Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Modulus ◽  
Chain Extender ◽  
Compression Stress ◽  
Supramolecular Hydrogel ◽  
Elongation At Break

Polyurethane–urea supramolecular hydrogel with excellent mechanical and processible properties is developed. The mechanical properties including shear modulus, elongation at break, tensile strength and compression stress can be adjusted by altering the diisocyanate content.

scholarly journals Thermally Self-Healing Graphene-Nanoplate/Polyurethane Nanocomposites via Diels–Alder Reaction through a One-Shot Process

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 434 ◽  
Author(s):  
Cho-Rong Oh ◽  
Sang-Hyub Lee ◽  
Jun-Hong Park ◽  
Dai-Soo Lee
Keyword(s):  
Molecular Design ◽  
Alder Reaction ◽  
Chain Extender ◽  
Diels Alder ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Diels Alder Reaction ◽  
A Chain ◽  
The Fourier Transform

Thermally self-healing graphene-nanoplate/polyurethane (GNP/PU) nanocomposites were prepared via a bulk in-situ Diels–Alder (DA) reaction. Graphene-nanoplate (GNP) was used as a reinforcement and crosslinking platform by a DA reaction with a furfuryl-based chain extender of polyurethane (PU). Results showed that a DA reaction occurred in GNP during the PU forming cure process. This procedure is simple and solvent free because of the absence of any independent surface modification process. Through the calculation of the interfacial tensions, the conditions of the bulk in-situ DA reaction were determined to ensure that GNP and the furfuryl group can react with each other at the interface during the curing process without a solvent. The prepared composites were characterized in terms of thermal, mechanical, and thermally self-healing properties via the DA reaction. In the PU capable of a DA reaction (DPU), characteristic peaks of DA and retro DA reactions were observed in the Fourier transform infrared (FT-IR) spectroscopy and endothermic peaks of retro DA reactions appeared in differential scanning calorimetry (DSC) thermograms. The DPU showed significantly enhanced physical properties and chemical resistance. The thermally self-healing capability was confirmed at 110 °C via the retro DA reactions. It is inferred that thermally self-healable crosslinked GNP/PU nanocomposites via DA reactions could be prepared in a simple bulk process through the molecular design of a chain extender for the in-situ reaction at the interface.

Synthesis of flexible poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) bioplastics by ring-opening polymerization in the presence of chain extender

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 423-429
Author(s):  
Yodthong Baimark ◽  
Wuttipong Rungseesantivanon ◽  
Natcha Prakymoramas
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Glycol ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Chain Extender ◽  
Degree Of Crystallinity ◽  
Melt Flow ◽  
Gel Content ◽  
Ce Content

AbstractPoly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) (PLLA-PEG-PLLA) is found to be more flexible than PLLA due to the flexibility of PEG middle blocks. Melt flow and mechanical properties of PLLA-PEG-PLLA were improved through post melt blending with a chain extender (CE). In this work, in situ chain-extended PLLA-PEG-PLLAs were synthesized by ring-opening polymerization in the presence of Joncryl® CE. The influence of CE content (1.0, 2.0, and 4.0 phr) on the gel content, melt flow index (MFI), thermal properties, and mechanical properties of the obtained in situ chain-extended PLLA-PEG-PLLAs was investigated. The gel content of in situ chain-extended PLLA-PEG-PLLA increased while the MFI and degree of crystallinity significantly decreased with increasing CE content. The in situ chain-extended PLLA-PEG-PLLA with 1.0 phr CE showed the best tensile properties. The extensibility of in situ chain-extended PLLA-PEG-PLLA films decreased when the CE contents were higher than 1.0 phr. These in situ chain-extended PLLA-PEG-PLLA films can be used as highly flexible bioplastics.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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