scholarly journals Temperature-modulated DSC study of network formation via Thiol-Isocyanate “click” reaction

2016 ◽  
Vol 19 (2) ◽  
pp. 78-87
Author(s):  
Ha Tran Nguyen ◽  
Thu Thi Le Nguyen ◽  
Thang Van Le ◽  
Lam Le
Keyword(s):  
Network Formation ◽  
Click Reaction ◽  
Polymer Networks ◽  
Polymer Materials ◽  
Modulated Dsc ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Crosslinked Polymer ◽  
Temperature Modulated Dsc ◽  
Influence Of Temperature On

The thiol-isocyanate chemistry was used to create crosslinked polymer networks without the use of solvent and catalyst. The preliminary study of a model thiol-isocyanate reaction was performed to confirm the “efficient linking” feature of the reaction, as indicated by online FTIR method. Temperature-modulated differential scanning calorimetry (TMDSC) was used to characterize the occurrence of the networks thiol-isocyanate reaction between multifunctional reactants, the influence of temperature on the reaction rate and the glass transition temperatures of the partially and fully cured networks. The investigation could pave the way for the design and tailoring of new cross-linked polymer materials for on-demand applications.

Temperature-modulated DSC studies of time evolution of the polymorphic structure of PA6/clay nanocomposites

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiong-Yan Zhao
Keyword(s):  
Solid State ◽  
Annealing Time ◽  
Modulated Dsc ◽  
Clay Nanocomposites ◽  
Polymorphic Behavior ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Dsc Studies ◽  
Temperature Modulated Dsc ◽  
Twin Screw

AbstractTwo PA 6/clay nanocomposites, NCN5 and NCN10 with 5 and 10% (wt %) clay, respectively, were prepared by a twin screw extruder. The effects of annealing including solid-state annealing and melt-state annealing on the polymorphic behavior and thermal property of nanocomposites have been comparatively studied as a function of annealing time using Modulated Differential Scanning Calorimetry (MDSC). It was demonstrated that NCN5 and NCN10 exhibit a similar polymorphic behavior when they were annealed in solid-state for different durations. As the annealing temperature was elevated to 245 °C (melt-state annealing), significant differences in thermal behavior and polymorphism between NCN5 and NCN10 could be found. For NCN5, the α structure became the absolutely dominating crystalline phase independent of the annealing durations, for NCN10, however, the formation of γ structure is greatly enhanced and longer annealing time would amplify this phenomenon. Moreover, a low-temperature endothermic peak was observed around 180 °C in both NCN5 and NCN10 samples which was also found to strongly depend on the thermal history.

Effect of CMP Pad Exposure to Aqueous Media on the Pad Properties. Part 1. Dynamic Mechanical and Modulated DSC Analysis

2002 ◽  
Vol 732 ◽  
Author(s):  
A. Tregub ◽  
M. Moinpour ◽  
J. Sorooshian
Keyword(s):  
Aqueous Media ◽  
Mechanical Analysis ◽  
Fickian Diffusion ◽  
Modulated Dsc ◽  
Buffer Solution ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Ph Buffer Solution ◽  
Ph Buffer

AbstractSoaking of polyurethane-based CMP pad in oxide slurry, de-ionized water, and pH buffer solution, and its effect on thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis and Modulated Differential Scanning Calorimetry. Pad softening due to soaking was established, and softening mechanisms are discussed. Diffusion of the aqueous medias to polyurethane pad was described using Fickian diffusion model.

Differential scanning calorimetry (DSC) and temperature-modulated DSC study of three mouthguard materials☆

2007 ◽  
Vol 23 (12) ◽  
pp. 1492-1499 ◽  
Author(s):  
F MENG ◽  
S SCHRICKER ◽  
W BRANTLEY ◽  
D MENDEL ◽  
R RASHID ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Modulated Dsc ◽  
Scanning Calorimetry ◽  
Temperature Modulated Dsc

Cellulose nanocrystals reinforced shape memory polymer cardiovascular stent

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yu Chen ◽  
Irina Tatiana Garces ◽  
Tian Tang ◽  
Cagri Ayranci
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermo Gravimetric Analysis ◽  
Modulated Dsc ◽  
Recovery Ratio ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Ratio Measurement ◽  
Content Type

Purpose The purpose of this paper is to demonstrate an innovative, fast and low-cost method to fabricate customized stents using polyurethane-based shape memory polymers composite reinforced by cellulose nanocrystal (CNC), achieved by a commercial desktop extrusion-based additive manufacturing (EBAM) device. Design/methodology/approach The composite filament for printing the stents was prepared by a two-step melt-compounding extrusion process. Afterward, the stents were produced by a desktop EBAM printer. Thermal characterizations, including thermo-gravimetric analysis (TGA) and modulated differential scanning calorimetry (modulated DSC), were conducted on stent samples and filament samples, respectively. Then the stents were programmed under 45°C. Recovery characterizations, including recovery force and recovery ratio measurement, were conducted under 40°C. Findings TGA results showed that the materials were stable under the printing temperature. Modulated DSC results indicated that, with the addition of CNCs, the glass transition temperature of the material dropped slightly from 39.7°C at 0 Wt.% CNC to 34.2°C at 7 Wt.% CNC. The recovery characterization showed that the stents can exert a maximum recovery force of 0.4 N/mm when 7 Wt.% of CNCs were added and the maximum recovery ratio of 35.8% ± 5.1% was found when 4 Wt.% of CNCs were added. The addition of CNC improved both the recovery ratio and the recovery force of the as-prepared stents. Originality/value In terms of recovery force, the as-prepared stents out-performed commercially available stents by 30 times. In addition, additive manufacturing offers more flexibility in the design and fabrication of customized cardiovascular stents.

Interpenetrating polymer networks formed by cyanate esters and phenylethynyl-terminated imides

2016 ◽  
Vol 29 (5) ◽  
pp. 556-568 ◽  
Author(s):  
Christoph Meier ◽  
Patricia P Parlevliet ◽  
Manfred Döring
Keyword(s):  
Polymer Networks ◽  
Covalent Bond ◽  
High Heat ◽  
Interpenetrating Polymer Networks ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermal Gravimetry ◽  
Pendent Group ◽  
Very High ◽  
End Group

An oligomeric phenylethynyl-terminated imide (PETI) has been formulated with a cyanate ester (CE) with and without the addition of a compatibilizer 2,2′-diallylbisphenol A (DABPA) forming interpenetrating polymer networks (IPNs). Modulated differential scanning calorimetry (mDSC) was used to monitor the curing of the resin mixtures. The formation of various resulting IPNs was verified using mDSC, dynamical mechanical thermoanalysis (DMTA), thermal gravimetry analysis and scanning electron microscopy. Furthermore, it could be shown by mDSC and DMTA that a covalent bond of the separated CE and PETI networks could be achieved by the addition of DABPA. In this regard, a reaction mechanism is proposed for the cross-linking reaction between the allylic pendent group of DABPA and the phenylethynyl end-group of the PETI resin. The cured resin specimens showed to have very high heat resistance and very high glass transition temperatures up to 330°C.

Quasi-isothermal temperature-modulated differential scanning calorimetry (TMDSC) for the separation of reversible and irreversible thermodynamic changes in glass transition and melting ranges of flexible macromolecules

2009 ◽  
Vol 81 (10) ◽  
pp. 1931-1952 ◽  
Author(s):  
Bernhard Wunderlich
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermal Analyses ◽  
Data Bank ◽  
Irreversible Thermodynamic ◽  
Modulated Dsc ◽  
Glass Transitions ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Heat Capacity Measurements

With standard differential scanning calorimetry (DSC), it is possible to derive calorimetric data for equilibrium or metastable samples. The introduction of temperature-modulated DSC (TMDSC) permits in its quasi-isothermal (non-scanning) mode (TMDC), long-time apparent heat capacity measurements of high precision (±1 %). For flexible molecules, heat capacity measurements from the various calorimetric methods could be combined in the ATHAS Data Bank, which now contains experimental data for over 200 materials. These data were linked to the vibrational and large-amplitude motion of the constituent atoms and molecules, to provide a base for the judgement of the thermal analyses, extending outside the range of equilibrium or metastability with an error of only 2-5 %. The TMDC together with DSC is now able to quantitatively assess the reversibility of thermal processes. A sufficient number of systems have been analyzed in this fashion to develop better understanding of macro-, micro-, and nanophases of flexible macromolecules. The new concepts discussed are: (1) multiple glass transitions due to possible rigid-amorphous fractions (RAFs) and glass transitions within crystals, both observed in semicrystalline macromolecules, and (2) locally reversibly melting on the surface of chain-folded crystals. The locally reversible melting decreases with crystal perfection and also disappears when the chains become rigid.

The interplay between network morphology and degradation kinetics of polymers: Theoretical and experimental analysis by means of a 2D model system

MRS Advances ◽  
2019 ◽  
Vol 5 (12-13) ◽  
pp. 679-691
Author(s):  
Rainhard Machatschek ◽  
Shivam Saretia ◽  
Andreas Lendlein
Keyword(s):  
Network Formation ◽  
Polymer Networks ◽  
Polymer Materials ◽  
Quantitative Prediction ◽  
Cross Linking ◽  
Degradation Behavior ◽  
Network Nodes ◽  
The Real ◽  
Real Network ◽  
The Ideal

ABSTRACTNetwork formation by cross-linking is a common method to incorporate functions like elastic deformability, shape-memory capability or hydrogel formation into polymer materials for medical applications. Since these materials are often intended to degrade, their design would benefit from a quantitative prediction of the interdependence between network architecture and degradation behavior. Here, we introduce a quantitative description of the degradation behavior of polymer networks. A simplified model was developed under the assumption of having an ideal network, where all network strands are terminated by network nodes and each node is connected to the same number of strands. To describe the degradation of real networks, the model was modified by allowing for a varying connectivity of network nodes, which also included free chain-ends. The models were validated by comparison with Langmuir monolayer degradation data from 2D networks formed by cross-linking oligo(ε-caprolactone)diols with dialdehydes. We found that both the ideal network hypothesis and the real network model were in excellent agreement with the experimental data, with the ideal network hypothesis requiring longer network strands than the real network to result in the same degradation behavior. The models were further used to calculate the degradation curves of the corresponding, non cross-linked molecules. By comparison, it was found that the network formation increases the time required to reach 50% degradation of oligo(ε-caprolactone)diols by only 20%. This difference mainly arises from attaching free chain ends to network points.

scholarly journals Reversible supramolecular adhesives formed by metallacycle-crosslinked polymer networks via amino‑yne click reaction

Giant ◽  
2020 ◽  
Vol 4 ◽  
pp. 100034
Author(s):  
Kai Gao ◽  
Zeyuan Zhang ◽  
Lingzhi Ma ◽  
Long Chen ◽  
Xingxing Chen ◽  
...  
Keyword(s):  
Click Reaction ◽  
Polymer Networks ◽  
Crosslinked Polymer
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