Understanding copolymerisation kinetics for the design of functional copolymers <i>via</i> free radical polymerisation

Boulding, Natasha A.; Millican, Jonathan M.

doi:10.1039/c9py01294j

Cited by 17 publications

(15 citation statements)

References 64 publications

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“…Owing to the versatility of monomer compatibility and the precise control on the degree of polymerization (DP) of monomers, , the RAFT technology was used to synthesize a series of poly(MPC)-based precursor polymers named as PMFMa, PMLA, PMF, and PMMa with different ratios of FPMA, MAABO, LAEMA, and AEMA units (Table ). Due to the copolymerization of methacrylates (MPC and FPMA) and methacrylamides (MAABO, LAEMA, and AEMA), which have different reactivities, − the obtained copolymers are not completely random. As the backbone unit, the conversion of MPC monomer was controlled around 50% to avoid the side reaction or termination reaction as far as possible.…”

Section: Resultsmentioning

confidence: 99%

Dual-Cross-Linked Network Hydrogels with Multiresponsive, Self-Healing, and Shear Strengthening Properties

Zhao

Diaz‐Dussan

et al. 2020

Biomacromolecules

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Dual-cross-linked network (DCN) hydrogels with multiresponsive and self-healing properties are attracting intensive interests due to their enhanced mechanical strength for a wide range of applications. Herein, we developed a DCN hydrogel that combines a dynamic imine and a benzoxaboronic ester with a neutral pK a value (∼7.2) as dual linkages and contains biocompatible zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] as the backbone. Oscillatory rheology result indicated shear strengthening mechanical properties compared to the singlecross-linked network (SCN) hydrogels, which use either imine bond or benzoxaboronic ester as the linkage alone. Due to the coexistence of stimuliresponsive imine and benzoxaboronic ester, the DCN hydrogels show sensitive multiple responsiveness to pH, sugar, and hydrogen peroxide. The dynamic nature of the dual linkages endows the DCN hydrogels with excellent self-healing ability after fracture. More importantly, the excellent biocompatibility and performance in three-dimensional (3D) cell encapsulation were established by a cytotoxicity Live/Dead assay, indicating DCN hydrogel's great potential as a cell culture scaffold. The biocompatible poly(MPC)-based backbone and the rapid formation of the cross-linking network make the DCN hydrogels promising candidates for future biomedical applications.

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Section: Resultsmentioning

confidence: 99%

Dual-Cross-Linked Network Hydrogels with Multiresponsive, Self-Healing, and Shear Strengthening Properties

Zhao

Diaz‐Dussan

et al. 2020

Biomacromolecules

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“…r nBA (r 2 )~1 indicated similar reactivity of nBA and CyA to the propagating nBA radical chain ends, while r CyA (r 1 ) < 1 suggested that nBA has a preference towards adding to the CyA terminated propagating radical chain ends. The lower self-propagation compared to cross-propagation of CyA monomers was presumably attributed to its bulkier cytosine pendant unit, which inhibited the addition of another CyA monomer to a CyAterminated radical [33]. Although the calculated reactivity ratios demonstrated that nBA propagates favorably at low conversions and thereby generating nBA-enriched polymer chains, it is of great interest to probe if the polymer displays a composition gradient along the polymer chain due to concentration effects at higher monomer conversions.…”

Section: Synthesis Of Cya and Ucya Triblock Copolymermentioning

confidence: 98%

Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

et al. 2021

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This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.

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“…This is explained by the fact that PEO 5 MEMA is even more preferable for cross-polymerization than MMA. This assumption may be justified by recent studies of Boulding et al [41], where authors stated that the reactivity ratio of MMA is higher if compared to the used PEG-methacrylate during the free radical polymerization of such monomers.…”

Section: Synthesis Of P(st-co-peo 5 Mema) Copolymersmentioning

confidence: 99%

Synthesis and Study of Thermoresponsive Amphiphilic Copolymers via RAFT Polymerization

et al. 2022

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Synthesis and study of well-defined thermoresponsive amphiphilic copolymers with various compositions were reported. Kinetics of the reversible addition-fragmentation chain transfer (RAFT) (co)polymerization of styrene (St) and oligo(ethylene glycol) methyl ether methacrylate (PEO5MEMA) was studied by size exclusion chromatography (SEC) and 1H NMR spectroscopy, which allows calculating not only (co)polymerization parameters but also gives valuable information on RAFT (co)polymerization kinetics, process control, and chain propagation. Molecular weight Mn and dispersity Đ of the copolymers were determined by SEC with triple detection. The detailed investigation of styrene and PEO5MEMA (co)polymerization showed that both monomers prefer cross-polymerization due to their low reactivity ratios (r1 < 1, r2 < 1); therefore, the distribution of monomeric units across the copolymer chain of p(St-co-PEO5MEMA) with various compositions is almost ideally statistical or azeotropic. The thermoresponsive properties of p(St-co-PEO5MEMA) copolymers in aqueous solutions as a function of different hydrophilic/hydrophobic substituent ratios were evaluated by measuring the changes in hydrodynamic parameters under applied temperature using the dynamic light scattering method (DLS).

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Understanding copolymerisation kinetics for the design of functional copolymers via free radical polymerisation

Abstract: We report the free radical copolymerisation kinetics and co-monomer sequence distribution for a series of functional copolymers based on MMA.

Cited by 17 publications

References 64 publications

Dual-Cross-Linked Network Hydrogels with Multiresponsive, Self-Healing, and Shear Strengthening Properties

Dual-Cross-Linked Network Hydrogels with Multiresponsive, Self-Healing, and Shear Strengthening Properties

Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

Synthesis and Study of Thermoresponsive Amphiphilic Copolymers via RAFT Polymerization

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