Effect of comonomer concentration and functionality on photopolymerization rates, mechanical properties and heterogeneity of the polymer

Young, Jennifer S.; Kannurpatti, Anandkumar R.; Bowman, Christopher N.

doi:10.1002/(sici)1521-3935(19980601)199:6<1043::aid-macp1043>3.3.co;2-q

Cited by 38 publications

(63 citation statements)

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“…A higher peak means a longer distance between crosslink points. It is reported that the heterogeneity will increase as the crosslink agent concentration increases within a copolymer system [53]. From Figure 3, with the addition of MPS in the formulations, whether in two-component or three-component PI formulations, the tan δ peak values increased slightly, which indicated that the mobility of copolymer chain was enhanced.…”

Section: Discussionmentioning

confidence: 92%

“…Comparing the storage moduli of the copolymers prepared with the two-component or three-component PI, the values of the two-component were higher than those of the three-component in the dry condition. Mechanical properties have been correlated with the DC of monomers [42, 53, 54], and the DC of the three-component PI systems was higher than that of the two-component PI (see Figure 1E). These contradictory results could be attributed to the long-tail alkyl group of iodonium salt (OPPIH), which can act as a plasticizer in the copolymer.…”

Section: Discussionmentioning

confidence: 99%

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Mimicking nature: Self-strengthening properties in a dental adhesive

Song

et al. 2016

Acta Biomaterialia

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Chemical and enzymatic hydrolysis provoke a cascade of events that undermine methacrylate-based adhesives and the bond formed at the tooth/composite interface. Infiltration of noxious agents, e.g. enzymes, bacteria, and so forth, into the spaces created by the defective bond will ultimately lead to failure of the composite restoration. This paper reports a novel, synthetic resin that provides enhanced hydrolytic stability as a result of intrinsic reinforcement of the polymer network. The behavior of this novel resin, which contains γ-methacryloxyproyl trimethoxysilane (MPS) as its Si-based compound, is reminiscent of self-strengthening properties found in nature. The efforts in this paper are focused on two essential aspects: the visible-light irradiation induced (photoacid-induced) sol-gel reaction and the mechanism leading to intrinsic self-strengthening. The FTIR band at 2840 cm−1 corresponding to CH3 symmetric stretch in −Si−O−CH3 was used to evaluate the sol-gel reaction. Results from the real-time FTIR indicated that the newly developed resin showed a limited sol-gel reaction (<5%) during visible-light irradiation, but after 48h dark storage, the reaction was over 65%. The condensation of methoxysilane mainly occurred under wet conditions. The storage moduli and glass transition temperature of the copolymers increased in wet conditions with the increasing MPS content. The cumulative amounts of leached species decreased significantly when the MPS-containing adhesive was used. The results suggest that the polymethacrylate-based network, which formed first as a result of free radical initiated polymerization, retarded the photoacid-induced sol-gel reaction. The sol-gel reaction provided a persistent, intrinsic reinforcement of the polymer network in both neutral and acidic conditions. This behavior led to enhanced mechanical properties of the dental adhesives under conditions that simulate the wet, oral environment.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Mimicking nature: Self-strengthening properties in a dental adhesive

Song

et al. 2016

Acta Biomaterialia

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“…The original viscosity of the formulation and the functionality of the monomer determine the maximum polymerization rate and its appearance time, respectively. 47 The viscosities of the experimental adhesive formulations are less than the control (unpublished data), which is probably due to the lower molecular weight of BMPMOB and the decreased concentration of BisGMA in the experimental formulations. When the BMPMOB weight percent is over 25%, the bimodal polymerization rate can be observed from the R p -conversion curves in Figure 5.…”

Section: Discussionmentioning

confidence: 92%

“…Usually, with the increase in functionality, the earlier and steeper autoacceleration can be observed at a lower double bond DC. 47 This is due to the localized increases in viscosity of the polymerizing system, which slows termination reactions. The original viscosity of the formulation and the functionality of the monomer determine the maximum polymerization rate and its appearance time, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…It is reported that the heterogeneity will increase as the crosslink agent concentration increases within a copolymer system. 47 In the current work, BMPMOB can be considered to be a trifunctional comonomer. The broad glass transition range contributes to heterogeneous network containing both highly crosslinked and less densely crosslinked regions.…”

Section: Discussionmentioning

confidence: 99%

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Synthesis and evaluation of novel dental monomer with branched carboxyl acid group

Song

et al. 2014

J Biomed Mater Res

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To enhance the water miscibility and increase the mechanical properties of dentin adhesives, a new glycerol-based monomer with vinyl and carboxylic acid, 4-((1,3-bis(-methacryloyloxy)propan-2-yl)oxy)-2-methylene-4-oxobutanoic acid (BMPMOB), was synthesized and characterized. Dentin adhesive formulations containing 2-hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (BisGMA), and BMPMOB were characterized with regard to real-time photopolymerization behavior, water sorption, dynamic mechanical analysis, and microscale three-dimensional internal morphologies and compared with HEMA/BisGMA controls. The experimental adhesive copolymers showed higher glass transition temperature and rubbery moduli, as well as improved water miscibility compared to the controls. The enhanced properties of the adhesive copolymers indicated that BMPMOB is a promising comonomer for dental restorative materials.

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Photopolymerized Triazole‐Based Glassy Polymer Networks with Superior Tensile Toughness

Han

Baranek

Worrell

et al. 2018

Adv Funct Materials

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Photopolymerization is a ubiquitous, indispensable technique widely applied in applications from coatings, inks, and adhesives to thermosetting restorative materials for medical implants, and the fabrication of complex macro-scale, microscale, and nanoscale 3D architectures via additive manufacturing. However, due to the brittleness inherent in the dominant acrylate-based photopolymerized networks, a significant need exists for higher performance resin/oligomer formulations to create tough, defect-free, mechanically ductile, thermally and chemically resistant, high modulus network polymers with rapid photocuring kinetics. This study presents densely cross-linked triazole-based glassy photopolymers capable of achieving preeminent toughness of ≈70 MJ m−3 and 200% strain at ambient temperature, comparable to conventional tough thermoplastics. Formed either via photoinitiated copper(I)-catalyzed cycloaddition of monomers containing azide and alkyne groups (CuAAC) or via photoinitiated thiol-ene reactions from monomers containing triazole rings, these triazole-containing thermosets completely recover their original dimensions and mechanical behavior after repeated deformations of 50% strain in the glassy state over multiple thermal recovery–strain cycles.

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Effect of comonomer concentration and functionality on photopolymerization rates, mechanical properties and heterogeneity of the polymer

Cited by 38 publications

References 0 publications

Mimicking nature: Self-strengthening properties in a dental adhesive

Mimicking nature: Self-strengthening properties in a dental adhesive

Synthesis and evaluation of novel dental monomer with branched carboxyl acid group

Photopolymerized Triazole‐Based Glassy Polymer Networks with Superior Tensile Toughness

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