Gelation behavior of thermoplastic-modified epoxy systems during polymerization-induced phase separation

Liu, Yi; Zhong, Xinhui; Yu, Yingfeng

doi:10.1007/s00396-010-2288-5

Cited by 23 publications

(19 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We demonstrate that by tailoring the prepolymer molecular weight while directly controlling the rate of network formation via photoirradiation, varying network morphologies can be formed. Previous work into the impact of prepolymer or additive size in heterogeneous networks formed via PIPS has focused on thermally cured epoxy-based resins[24]. Here, we show that using both prepolymer molecular weight and the rate of network formation we can define the limits where PIPS is restricted from physical and energetic limitations in an ambient-cured photopolymerization.…”

Section: Introductionmentioning

confidence: 70%

Modification of linear prepolymers to tailor heterogeneous network formation through photo-initiated polymerization-induced phase separation

Szczepanski

Stansbury

2015

Polymer

View full text Add to dashboard Cite

Polymerization-induced phase separation (PIPS) was studied in ambient photopolymerizations of triethylene glycol dimethacrylate (TEGDMA) modified by poly(methyl methacrylate) (PMMA). The molecular weight of PMMA and the rate of network formation (through incident UV-irradiation) were varied to influence both the promotion of phase separation through increases in overall free energy, as well as the extent to which phase development occurs during polymerization through diffusion prior to network gelation. The overall free energy of the polymerizing system increases with PMMA molecular weight, such that PIPS is promoted thermodynamically at low loading levels (5 wt%) of a higher molecular weight PMMA (120 kDa), while a higher loading level (20 wt%) is needed to induce PIPS with lower PMMA molecular weight (11 kDa), and phase separation was not promoted at any loading level tested of the lowest molecular weight PMMA (1 kDa). Due to these differences in overall free energy, systems modified by PMMA (11 kDa) underwent phase separation via Nucleation and Growth, and systems modified by PMMA (120 kDa), followed the Spinodal Decomposition mechanism. Despite differences in phase structure, all materials form a continuous phase rich in TEGDMA homopolymer. At high irradiation intensity (Io=20mW/cm2), the rate of network formation prohibited significant phase separation, even when thermodynamically preferred. A staged curing approach, which utilizes low intensity irradiation (Io=300µW/cm2) for the first ~50% of reaction to allow phase separation via diffusion, followed by a high intensity flood-cure to achieve a high degree of conversion, was employed to form phase-separated networks with reduced polymerization stress yet equivalent final conversion and modulus.

show abstract

Section: Introductionmentioning

confidence: 70%

Modification of linear prepolymers to tailor heterogeneous network formation through photo-initiated polymerization-induced phase separation

Szczepanski

Stansbury

2015

Polymer

View full text Add to dashboard Cite

show abstract

“…In crosslinking systems, the onset of gelation plays an important role in the potential magnitude of phase separation. In some cases, such as in thermoplastic‐modified epoxy systems, demixing precedes gelation, which is then responsible for stabilizing the heterogeneous structure . Other work has demonstrated that for polymer‐dispersed liquid crystals, turbidity development (used as an indication of onset of phase separation) occurs late in polymerization based on liquid–gel demixing .…”

Section: Resultsmentioning

confidence: 99%

Tailoring heterogeneous polymer networks through polymerization-induced phase separation: influence of composition and processing conditions on reaction kinetics and optical properties

Pfeifer

Shelton

Szczpanski

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

View full text Add to dashboard Cite

Polymerization‐induced phase separation from an all‐monomeric system by direct copolymerization offers the formation of heterogeneous polymeric structures without reliance on polymer blends, block copolymers, or interpenetrating polymer networks. This study examines the potential for the formation of compositional heterogeneity in copolymer networks obtained by free‐radical photopolymerizations of initially homogeneous mixtures of bisphenol A glycidyl dimethacrylate and isodecyl methacrylate as the comonomer ratios and polymerization conditions are varied. Comonomer proportions that control thermodynamic stability prior to (as determined by cloud point measurements) and during [as determined by turbidity measurements coupled with near‐infrared (IR) spectroscopy] polymerization were shown to be a more influential factor on phase separation than irradiance‐imposed kinetic control of the photopolymerization process. Through photorheometry coupled with near‐IR and ultraviolet–visible (UV–Vis), the onset of phase separation was shown to occur at very low conversions and always prior to gelation (as estimated by the crossover of G′/G″). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1796–1806

show abstract

“…Figure 11 shows the relation between flexural strength values with blending ratio for the ternary blend under study, it can be concluded that the behavior of blend (A) different from that the behavior of blend (B). This difference depend on two factor, the first factor is the presence of polymer (UPE) in the blend (A) which consider brittle polymer which leading to increase the flexural strength value at the ratio (5 wt.%) and then the flexural strength of blend (A) decreases with increasing of the blending ratio due to the occurring of the plasticization phenomenon (Liu, Zhong, & Yu, 2010) especially at the ratio (10 wt.%), the second factor return to presence the polymer (PVC) in the blend (B) which causes decreasing of flexural strength at the initial ratio of mixing but increasing at the higher ratios (15, 20 wt.%).…”

Section: Hardness Testmentioning

confidence: 99%

A Study on the Mechanical Properties for Ternary Polymer Blends

Hameed¹

2017

JMSR

View full text Add to dashboard Cite

In this work, two ternary polymer blends were prepared by mixing EP with (UP/PSR) and (PVC/PSR) respectively. Different mixing ratios were used (5, 10, 15 and 20) wt.% of the added polymers. Impact, tensile, compression, flexural and hardness tests were performed on the prepared blends. The results of testing showed that the first ternary blend A (EP/UP/PSR) records tensile strength values higher than that of the second ternary blend B (EP/ PVC/PSR). At 20wt.% of mixing, the blend B records higher impact strength than that of the blend A. There is large difference in the flexural behavior between A and B blends where the blend A records the highest value of flexural strength (F.S) at (5wt.%) while the blend B records the highest value of (F.S) at (20wt.%). From compression test, it is obvious that the values of compressive strength decrease of blend B more than that of the blend A as well as the same behavior can be obtained through the hardness test.

show abstract

Gelation behavior of thermoplastic-modified epoxy systems during polymerization-induced phase separation

Cited by 23 publications

References 40 publications

Modification of linear prepolymers to tailor heterogeneous network formation through photo-initiated polymerization-induced phase separation

Modification of linear prepolymers to tailor heterogeneous network formation through photo-initiated polymerization-induced phase separation

Tailoring heterogeneous polymer networks through polymerization-induced phase separation: influence of composition and processing conditions on reaction kinetics and optical properties

A Study on the Mechanical Properties for Ternary Polymer Blends

Contact Info

Product

Resources

About