scholarly journals Synthesis of Lignin-Based MMA-co-BA Hybrid Resins from Cornstalk Residue via RAFT Miniemulsion Polymerization and Their Characteristics

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 968
Author(s):  
Yuzhi Xu ◽  
Ning Li ◽  
Guangbin Wang ◽  
Chunpeng Wang ◽  
Fuxiang Chu
Keyword(s):  
Chain Transfer ◽  
Mechanical Performance ◽  
Miniemulsion Polymerization ◽  
Value Added ◽  
Waste Biomass ◽  
Molecular Architecture ◽  
Scanning Calorimetry ◽  
Hybrid Resin ◽  
Reversible Addition ◽  
Transfer Method

The conversion of cornstalk lignin derived from the co-product of bio-refinery into value-added products such as polymeric material has remarkable environmental and economic potential. A novel bio-based methyl methacrylate copolymerized with butyl acrylate (MMA-co-BA) hybrid resin in our research was prepared by the reversible addition–fragmentation chain transfer method using lignin-graft-polyacrylamide (lignin-g-PAM) as a bio-derived macromolecular chain transfer agent. The molecular architecture of lignin-g-PAM and the lignin-based MMA-co-BA hybrid resin was elucidated using 1H nuclear magnetic resonance and attenuated total reflectance–Fourier transform infrared. The thermal behavior and mechanical performance of the resultant lignin-based MMA-co-BA hybrid resins were also investigated through thermogravimetric analysis, differential scanning calorimetry, and a stress–strain test, respectively. The lignin-based acrylate resins system exhibited structure-related thermal and mechanical properties. Compared with pure MMA-co-BA resin, the incorporation of lignin into various lignin-based MMA-co-BA graft copolymers resulted in an improved tensile strength and a higher Young’s modulus. This research could provide not only a new avenue to utilize waste biomass for high-value applications, but also a reference for designing new materials for coatings or adhesives.

scholarly journals Dextran-covered pH-sensitive oily core nanocapsules produced by interfacial Reversible Addition-Fragmentation chain transfer miniemulsion polymerization

2020 ◽  
Vol 569 ◽  
pp. 57-67 ◽  
Author(s):  
Laura Marcela Forero Ramirez ◽  
Ariane Boudier ◽  
Caroline Gaucher ◽  
Jérôme Babin ◽  
Alain Durand ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Miniemulsion Polymerization ◽  
Ph Sensitive ◽  
Reversible Addition

scholarly journals Polydopamine-Coated Paraffin Microcapsules as a Multifunctional Filler Enhancing Thermal and Mechanical Performance of a Flexible Epoxy Resin

2020 ◽  
Vol 4 (4) ◽  
pp. 174
Author(s):  
Giulia Fredi ◽  
Cordelia Zimmerer ◽  
Christina Scheffler ◽  
Alessandro Pegoretti
Keyword(s):  
Phase Change ◽  
Storage Modulus ◽  
Mechanical Performance ◽  
Value Added ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Management Capability ◽  
Deposition Parameters ◽  
Potential Applications ◽  
Ep Matrix

This work focuses on flexible epoxy (EP) composites containing various amounts of neat and polydopamine (PDA)-coated paraffin microcapsules as a phase change material (PCM), which have potential applications as adhesives or flexible interfaces with thermal management capability for electronics or other high-value-added fields. After PDA modification, the surface of PDA-coated capsules (MC-PDA) becomes rough with a globular appearance, and the PDA layer enhances the adhesion with the surrounding epoxy matrix, as shown by scanning electron microscopy. PDA deposition parameters have been successfully tuned to obtain a PDA layer with a thickness of 53 ± 8 nm, and the total PDA mass in MC-PDA is only 2.2 wt %, considerably lower than previous results. This accounts for the fact that the phase change enthalpy of MC-PDA is only marginally lower than that of neat microcapsules (MC), being 221.1 J/g and 227.7 J/g, respectively. Differential scanning calorimetry shows that the phase change enthalpy of the prepared composites increases with the capsule content (up to 87.8 J/g) and that the enthalpy of the composites containing MC-PDA is comparable to that of the composites with MC. Dynamic mechanical analysis evidences a decreasing step in the storage modulus of all composites at the glass transition of the EP phase, but no additional signals are detected at the PCM melting. PCM addition positively contributes to the storage modulus both at room temperature and above Tg of the EP phase, and this effect is more evident for composites containing MC-PDA. As the capsule content increases, the mechanical properties of the host EP matrix also increase in terms of elastic modulus (up to +195%), tensile strength (up to +42%), Shore D hardness (up to +36%), and creep compliance (down to −54% at 60 min). These effects are more evident for composites containing MC-PDA due to the enhanced interfacial adhesion.

RAFT Polymerization of Monomers with Highly Disparate Reactivities: Use of a Single RAFT Agent and the Synthesis of Poly(styrene-block-vinyl acetate)

2013 ◽  
Vol 66 (12) ◽  
pp. 1564 ◽  
Author(s):  
Lily A. Dayter ◽  
Kate A. Murphy ◽  
Devon A. Shipp
Keyword(s):  
Block Copolymers ◽  
Vinyl Acetate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Good Control ◽  
Scanning Calorimetry ◽  
Styrene Polymerization ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Group

A single reversible addition–fragmentation chain transfer (RAFT) agent, malonate N,N-diphenyldithiocarbamate (MDP-DTC) is shown to successfully mediate the polymerization of several monomers with greatly differing reactivities in radical/RAFT polymerizations, including both vinyl acetate and styrene. The chain transfer constants (Ctr) for MDP-DTC for both these monomers were evaluated; these were found to be ~2.7 in styrene and ~26 in vinyl acetate, indicating moderate control over styrene polymerization and good control of vinyl acetate polymerization. In particular, the MDP-DTC RAFT agent allowed for the synthesis of block copolymers of these two monomers without the need for protonation/deprotonation switching, as has been previously developed with N-(4-pyridinyl)-N-methyldithiocarbamate RAFT agents, or other end-group transformations. The thermal properties of the block copolymers were studied using differential scanning calorimetry, and those with sufficiently high molecular weight and styrene composition appear to undergo phase separation. Thus, MDP-DTC may be useful for the production of other block copolymers consisting of monomers with highly dissimilar reactivities.

Multisegmented polymers via step-growth and RAFT miniemulsion polymerization

2021 ◽  
Author(s):  
Thiago R. Guimarães ◽  
Laura Delafresnaye ◽  
Dewen Zhou ◽  
Christopher Barner-Kowollik ◽  
Per B. Zetterlund
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Miniemulsion Polymerization ◽  
Reversible Addition ◽  
Step Growth

We report a method to efficiently prepare multisegmented polymers via a combination of step-growth (SG) and reversible addition-fragmentation chain transfer (RAFT) polymerization.

Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization in Miniemulsion Based on In Situ Surfactant Generation

2011 ◽  
Vol 64 (8) ◽  
pp. 1033 ◽  
Author(s):  
S. R. Simon Ting ◽  
Eun Hee Min ◽  
Per B. Zetterlund
Keyword(s):  
Potassium Hydroxide ◽  
Colloidal Stability ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Miniemulsion Polymerization ◽  
High Energy ◽  
Reversible Addition ◽  
Raft Agent ◽  
Surface Active

Reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The best results were obtained using the RAFT agent 3-benzylsulfanyl thiocarbonyl sufanylpropionic acid (BSPAC), most likely as a result of the presence of a carboxylic acid functionality in the RAFT agent that renders it surface active and thus imparts increased colloidal stability. Stable final miniemulsions were obtained with no coagulum with particle diameters less than 200 nm. The results demonstrate that the RAFT miniemulsion polymerization of styrene employing the low energy in situ surfactant method is challenging, but that a system that proceeds predominantly by a miniemulsion mechanism can be achieved under carefully selected conditions.

Synthesis and characterization of poly(vinyl chloride-graft-2-vinylpyridine) graft copolymers using a novel macroinitiator by reversible addition-fragmentation chain transfer polymerization

e-Polymers ◽  
2014 ◽  
Vol 14 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Temel Öztürk ◽  
Melahat Göktaş ◽  
Bedrettin Savaş ◽  
Mustafa Işıklar ◽  
Mehmet Nuri Atalar ◽  
...  
Keyword(s):  
Vinyl Chloride ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Graft Copolymers ◽  
Monomer Concentration ◽  
Polymerization Reaction ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Poly Vinyl Chloride ◽  
Reversible Addition

AbstractSynthesis of poly(vinyl chloride-graft-2-vinylpyridine) graft copolymers was carried out by reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-vinylpyridine using a novel macroinitiator (RAFT macroinitiator). For this purpose, RAFT macroinitiator was obtained from the potassium salt of ethyl xanthogenate and poly(vinyl chloride) (PVC). Then the graft copolymers were synthesized by using RAFT macroinitiator and 2-vinylpyridine. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the polymerization reaction were studied. The effect of the reaction conditions on the heterogeneity index and molecular weight was also investigated. The block lengths of the graft copolymers were calculated by using 1H nuclear magnetic resonance (1H NMR) spectra. The block lengths of the copolymers could be adjusted by varying the monomer and initiator concentrations. The characterizations of the samples were carried out by using 1H NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, and fractional precipitation (γ value) techniques. RAFT polymerization is used to control the polymerization of 2-vinylpyridine over a broad range of molecular weights.

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