Phenolic Hyperbranched Polymers as Additives in Cationic Photopolymerization of Epoxy Systems

Sangermano, Marco; Priola, Aldo; Malucelli, Giulio; Bongiovanni, Roberta Maria; Quaglia, A.; Voit, Brigitte; Ziemer, Antje

doi:10.1002/mame.200300371

Cited by 76 publications

(53 citation statements)

References 25 publications

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“…The synthesized oxetane HBP contained a large number of reactive groups that could copolymerize with the oxetane resin, and at the same time it contained a significant number of phenolic groups that could interact with the carbocationic propagating species through a chain-transfer reaction, as demonstrated in previous works for epoxy 13 and oxetane 14 systems. These two reaction mechanisms were responsible for the increase in the crosslinking density through the incorporation of the highly branched and compact hyperbranched macromolecules and, therefore, for the increase in the T g values.…”

Section: Methodsmentioning

confidence: 84%

“…8,9 Just recently, our attention was focused on the use of HBPs in cationic photopolymerization. 5,[12][13][14] The cationic photoinduced process presents some advantages over the radical process, 15 particularly a lack of inhibition by oxygen, low shrinkage, good mechanical properties for UV-cured materials, and good adhesion properties for various substrates. Moreover, the monomers employed are generally less toxic and irritating.…”

Section: Introductionmentioning

confidence: 99%

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Cationic photopolymerization of oxetane‐functionalized hyperbranched polymers

Sangermano

Gianni

Malucelli

et al. 2005

J of Applied Polymer Sci

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An aliphatic-aromatic pehenolic hyperbranched starting material (HBP-OH) with phenolic end groups was 85% functionalized by a Mitsunobu reaction with oxetane groups (OXT-HBP). This new hyperbranched polyester was used, at a concentration of 5-20 wt %, as an additive for the cationic photopolymerization of a commercial oxetane-based resin, 4,4Ј-bis [(3-ethyl-3-ethyl-3-oxetanyl) methoxymethyl]biphenyl (OXBP). HBP-OXT acted as a multifunctional crosslinker, copolymerizing with the oxetane ring of the OXBP resin, reacting through chain transfer with the remaining phenolic OH groups, or doing both. The result was an increase in the glass-transition temperature due to the increase in the crosslinking density. An increase in the weight residue at a high temperature was found in the presence of HBP-OXT and was attributed to the presence of phenolic groups, which are commonly used as antioxidant additives.

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Section: Methodsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Cationic photopolymerization of oxetane‐functionalized hyperbranched polymers

Sangermano

Gianni

Malucelli

et al. 2005

J of Applied Polymer Sci

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“…A phenolic polyester HBP based on based on bis-(4 0 -hydroxyphenyl)pentanoic acid (HBP-OH, Mn ¼ 4000 g/mol, Mw ¼ 5500 g/mol, PD ¼ 1.38), [24] a oxetane functionalized HBP (HBP-OXT, Mn ¼ 1100 g/mol, Mw ¼ 7600 g/mol PD ¼ 9.9), [25] and a fluorinated functionalized HBP (HBPF, Mn ¼ 5100, Mw ¼ 22800, PD ¼ 4.52) [26] were synthesized as elsewhere reported.…”

Section: Methodsmentioning

confidence: 99%

“…In the case of the cationic polymerization, onium salts are used as photoinitiators to generate very strong Brö nsted acids upon photodecomposition. [24] The cationic photoinduced process presents some advantages compared to the radical one, [25] in particular lack of inhibition by oxygen, low shrinkage, good mechanical properties of the UV cured materials and good adhesion properties to various substrates. Besides, the monomers employed are generally characterized by being less toxic and irritant.…”

Section: Introductionmentioning

confidence: 99%

Hyperbranched Polymers in Cationic UV Curing

Sangermano

Amerio

Gianni

et al. 2007

Macromolecular Symposia

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Summary: A wide range of hyperbranched polymers (HBP) was synthesized and investigated as additives in cationic photopolymerization of epoxy systems. The HBP were inserted into the polymeric network either by a copolymerization or through a chain transfer reaction involving the phenolic hydroxyl groups. By varying the type and concentration of HBP a modification of the bulk properties of photocured films was induced. An increase of toughness properties together with a flexibilization was obtained without affecting the processability and the viscosity of the photocurable mixture. In the presence of fluorine-containing HBP, a surface modification was induced.

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“…They are characterized by highly branched backbone with a large number of reactive groups, which provide them with excellent flow and processing properties. [14][15][16][17] Hyperbranched polyesters with different terminations have been successfully employed as multifunctional crosslinkers in coatings and in thermosets, with thermal and UV curing methods. Their addition to resin formulation has been explored to improve the thermal properties and modulus, to change the rheology and to improve the flow, the viscosity and the surface properties.…”

Section: Introductionmentioning

confidence: 99%

Rheological characterization of UV‐curable epoxy systems: Effects of o‐Boehmite nanofillers and a hyperbranched polymeric modifier

Corcione¹,

Frigione²,

Acierno³

2009

J of Applied Polymer Sci

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An organo-modified Boehmite (o-Boehmite) was used to prepare nanocomposite UV-curing coatings, based on a cycloaliphatic epoxy resin (3,4-epoxycyclohexylmethyl-3 0 ,4 0 -epoxycyclohexane carboxylate). A hyperbranched polymer (HBP) based on highly branched polyester, was also added to the resin, with the aim to modify its reactivity, such as a possible route to increase the toughness of the resin. Different amounts of the nanofiller and the HBP, ranging from 5 up to 20 wt % of resin, were dispersed into the resin in the presence of triarylsulfonium hexafluoroantimonate, as a photoinitiator for the UV curing of the resin. The rheological behavior of the formulations produced was studied as function of the shear rate and of the content of each filler using a cone and plate rheometer. A general increase in viscosity was observed with increasing the volume fraction of each filler and a moderate pseudoplastic behavior was observed when oBoehmite filler was added. A non-Newtonian behavior was observed with the incorporation of the HBP. The viscosity of the epoxy/boehmite resin mixtures was analyzed as function of the nanofiller volume fraction. In the case of epoxy/hyperbranched resin mixtures, the Cross equation was used to predict the viscosity of each formulation as a function of the shear rate and an appropriate relationship to predict the viscosity of each formulation as a function of the filler volume fraction, was determined.

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Phenolic Hyperbranched Polymers as Additives in Cationic Photopolymerization of Epoxy Systems

Cited by 76 publications

References 25 publications

Cationic photopolymerization of oxetane‐functionalized hyperbranched polymers

Cationic photopolymerization of oxetane‐functionalized hyperbranched polymers

Hyperbranched Polymers in Cationic UV Curing

Rheological characterization of UV‐curable epoxy systems: Effects of o‐Boehmite nanofillers and a hyperbranched polymeric modifier

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