Hyperbranched polyester as additives in filled and unfilled epoxy-novolac systems

Tian, Li; Qin, Huajun; Liu, Yi; Zhong, Xinhui; Yu, Yingfeng; Serra, Àngels

doi:10.1016/j.polymer.2012.10.028

Cited by 37 publications

(25 citation statements)

References 38 publications

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“…For epoxy curing, f(a) is usually taken in the form of (1 -a) n (n th -order reaction) or of a m (1 -a) n (autocatalytic reaction). The explicit temperature dependence of the rate constant is introduced by replacing k(T) with the Arrhenius equation (Equation (2)): (2) where A is the pre-exponential factor, E is the activation energy, and R is the gas constant. When a sample is heated at a constant rate, the explicit temporal dependence in Equation (2) is eliminated through the transformation shown by Equation (3): (3) where !…”

Section: Theoretical Calculationsmentioning

confidence: 99%

“…For example, epoxy resins possess excellent thermal stability, moisture resistance, chemical stability, superior electrical and mechanical properties and good adhesion to many substrates [1][2][3]. As well as known properties, such as, the superior mechanical and chemical properties of epoxy polymers are profited from the complicated curing processes, in which a low molecular weight oligomer is transformed into an infinite molecular weight polymer forming a three-dimensional network structure.…”

Section: Introductionmentioning

confidence: 99%

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Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

Zhao¹,

Zhang²,

Sun³

et al. 2014

Express Polym. Lett.

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Abstract. The curing kinetics and mechanism of epoxy novolac resin (DEN) and modified epoxy novolac resin (MDEN) with methanol etherified amino resin were studied by means of differential scanning calorimetry (DSC), Fourier transforminfrared (FT-IR) spectroscopy and chemorheological analysis. Their kinetics parameters and models of the curing were examined utilizing isoconversional methods, Flynn-Wall-Ozawa and Friedman methods. For the DEN mixture, its average activation energy (E a ) was 71.05 kJ/mol and the autocatalytic model was established to describe the curing reaction. The MDEN mixture exhibited three dominant curing processes, termed as reaction 1, reaction 2 and reaction 3; and their E a were 70.05, 106.55 and 101.91 kJ/mol, respectively. Besides, E a of reaction 1 was similar to that of DEN mixture, while E a of reactions 2 and 3 corresponded to that of the etherification reaction between hydroxyl and epoxide group. Moreover, these three dominant reactions were n th order in nature. Furthermore, their curing mechanisms were proposed from the results of DSC and FTIR. The chemorheological behavior was also investigated to obtain better plastics products via optimizing the processing schedules.

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Section: Theoretical Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

Zhao¹,

Zhang²,

Sun³

et al. 2014

Express Polym. Lett.

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show abstract

“…Additionally, for the same reason, the melt viscosity of PIC is much higher than other conventional polyesters with the same molecular weight. 28,29 Universal aromatic polyesters, especially poly(ethylene terephthalate) (PET) and poly-(butylene terephthalate) (PBT), can improve the mechanical properties of epoxy resins without compromising their thermal properties. 26,27 In order to meet the essential properties required in general plastics' applications, it is necessary to modify PIC even with decreased contents of biomass in resulting polymers.…”

Section: Introductionmentioning

confidence: 99%

A high-molecular-weight and high-T_g poly(ester carbonate) partially based on isosorbide: synthesis and structure–property relationships

Feng

Zhu

et al. 2015

Polym. Chem.

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A new family of high-molecular-weight poly(isosorbide carbonate-co-butylene terephthalate)s (PICBTs) partially based on renewable isosorbide (Is) were prepared by incorporating 1,4-butanediol (BD) and dimethyl terephthalate (DMT) into poly(isosorbide carbonate) (PIC), via a two-step bulk condensation polymerization. The incorporation of BD and DMT was developed to compensate for the low reactivity of Is and improve the molecular weight and processability of PIC, while retaining the rigidity and hence high glass transition temperature (T g ) of PIC. The resulting copolymers showed high number-average molecular weights ranging from 30 600 to 52 300 g mol −1 and tunable T g values from 69 to 146°C. The molecular structure of the novel poly(ester carbonate)s was confirmed using 1 H, 13 C, 2D-COSY and 2D-HSQC NMR techniques. 1 H NMR analysis revealed the random sequence distributions of the PICBTs. A systematic study on the structure-property relationship revealed that the thermal, dynamic mechanical and mechanical properties of the PICBTs strongly depended on their composition, which would enable molecular design of material properties with the desired balance of material rigidity, ductility, and biobased content. † Electronic supplementary information (ESI) available: 1 H NMR spectra of the PICBT copolymers; transmittance of PICBTs with varied feed content of Is; DSC heating traces of the PICBT copolymers; 1 H NMR spectra of PI 80 CBT 20 under isothermal degradation at 370°C; stress-strain curves of the PICBT copolymers. See

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“…Boltorn™, the commercially available hydroxyl-terminated hyperbranched polymers with aliphatic polyesters backbones have been extensively studied. [18][19][20][21] Results show that Boltorn™ can effectively improve toughness or the epoxy matrix. However, the strength and T g were signicantly compromised.…”

Section: -4mentioning

confidence: 99%

Simultaneous reinforcement and toughness improvement of an epoxy–phenolic network with a hyperbranched polysiloxane modifier

et al. 2018

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An epoxy-phenolic network is modified with hyperbranched polysiloxane (HBPSi). The addition of HBPSi-2, which has medium molecular weight, can significantly decrease the viscosity of the uncured epoxyphenolic system and increase the crosslinking density and homogeneity of the cured crosslinking network. With 10% HBPSi-2, the mechanical properties of the samples are improved comprehensively: tensile modulus and maximum strength increase by 11.4% and 36.2%, respectively, while elongation at break and impact strength increase by 153.8% and 186.7%, respectively. The comprehensive improvements in the mechanical properties are attributed to combined effects of crosslinking density, network rigidity, cohesive density and the matrix-modifier compatibility. What is more, HBPSi-2 also significantly increases the char yield of the material and decreases the thermal weight loss rate, indicating an improved thermal stability. All these results may provide a new strategy for toughness and strength improvement of the epoxy-phenolic network.

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Hyperbranched polyester as additives in filled and unfilled epoxy-novolac systems

Cited by 37 publications

References 38 publications

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

A high-molecular-weight and high-T_g poly(ester carbonate) partially based on isosorbide: synthesis and structure–property relationships

Simultaneous reinforcement and toughness improvement of an epoxy–phenolic network with a hyperbranched polysiloxane modifier

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Hyperbranched polyester as additives in filled and unfilled epoxy-novolac systems

Cited by 37 publications

References 38 publications

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

A high-molecular-weight and high-Tg poly(ester carbonate) partially based on isosorbide: synthesis and structure–property relationships

Simultaneous reinforcement and toughness improvement of an epoxy–phenolic network with a hyperbranched polysiloxane modifier

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Product

Resources

About

A high-molecular-weight and high-T_g poly(ester carbonate) partially based on isosorbide: synthesis and structure–property relationships