Maleimide end- capped polyether telechelics as novel toughening agents for unsaturated polyester resin

Jeemol, Poovathungal Abdulrahman; Mathew, Suresh; Nair, C. P. Reghunadhan

doi:10.1007/s10965-020-02197-z

Cited by 13 publications

(12 citation statements)

References 39 publications

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“…In previous works, maleimide-and itaconimide end-capped polyethers were chosen as the reactive oligomers. [16,17] The toughening effect was found to depend not only on the nature of the polyether but also on its concentration in the blend as well as how the end groups react or copolymerize with styrene/maleic groups. The reactivity of the end group of the polyether with styrene decides the spatial distribution of the polyether in the cured matrix.…”

Section: Resultsmentioning

confidence: 99%

“…In this backdrop, we examined maleic and itaconic end-capped polyethers and found that the terminal group does have an important role in deciding the toughening of the UPER. [16,17] It is of interest to see the impact of these polyethers when nadimide becomes their end group. Nadimide possesses an isolated unsaturation in its backbone.…”

Section: Resultsmentioning

confidence: 99%

“…When we blended with maleimide end-capped polyethers in our previous work, they showed a tremendous increase of fracture toughness (97%) and impact strength (118%) with 2.5 phr addition. [16] Comparison of % increase of fracture toughness for PPG, MPPG, and NPPG is revealed in Table 2.…”

Section: Tensile Flexural Impact and Fracture Propertiesmentioning

confidence: 99%

“…In previous work, we had examined the toughening effect of maleimide and itaconimide endfunctionalized polyethers in the same UPER. [16,17] In this paper, we examine the capabilities of nadimide endcapped telechelics of various polyethers in comparison to maleimide telechelics of the same for their capacity in toughening the conventional UPER. There are no reports of such studies so far.…”

Section: Introductionmentioning

confidence: 99%

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On the toughening of unsaturated polyester resins using nadimide end‐functionalized polyether telechelics

Jeemol

Mathew

Nair

2021

Polymer Engineering & Sci

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Copoly-propylene glycol (terephthalate-maleate) based unsaturated polyester resin (UPER) was modified with nadimide end-capped polyether telechelics namely, polypropylene glycol (PPG with molecular weight 2000, 1000, 400 g/mol), polytetramethylene oxide (PTMO with molecular weight 2000 g/mol) and polyethylene glycol (PEG with molecular weight 2000 g/mol) (NPPG/NPTMO/NPEG). The telechelic NPPG/NPTMO/NPEG were synthesized from the corresponding polyols (hydroxy telechelics) by reaction with 4-nadimido benzoyl chloride. These derivatives were characterized by chemical and spectral methods. Blends of UPER with varying amounts of NPPG/NPTMO/NPEG were prepared. Blending boosted the cohesive energy through enhanced crosslinking as reflected in the gel content of the cured matrices done in separate studies. It increased the fracture characteristics tremendously. The addition of 2.5 phr of the nadimide end functional polyether gave the maximum toughness. The crosslink density showed an initial increase on blending, but further addition of the telechelics did not make any change. The properties of the prepared blends were compared with maleimide end-capped polyether toughened UPE resins. It was concluded that the toughening effect of the polyether additive depends not only on its concentration but also on its distribution in the matrix as dictated by its reactivity ratio with styrene. The high reactivity of the nadimide groups did not create an ambiance good enough to get an acceptable distribution of the polyether segments conducive for a tough matrix. Whereas the maleimide end-capped polyether provides better toughening efficiency.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Tensile Flexural Impact and Fracture Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the toughening of unsaturated polyester resins using nadimide end‐functionalized polyether telechelics

Jeemol

Mathew

Nair

2021

Polymer Engineering & Sci

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“…It is in this backdrop, we introduced the maleimide functionalized polyether oligomers as toughening agent in UPR 12 . Precisely, these groups were introduced by reacting the polyols with maleimido benzoyl chloride.…”

Section: Introductionmentioning

confidence: 99%

Itaconimide telechelics of polyethers, synthesis, and their impact on mechanical properties of unsaturated polyester resins

Jeemol

Mathew

Nair

2021

Polymers for Advanced Techs

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The present work focuses on the evolution in the mechanical properties of an unsaturated polyester resin (UPR) on blending with itaconimide‐end terminated polyethers, namely, polypropylene glycol (I‐PPG), polyethylene glycol (I‐PEG), and polytetra methylene oxide (I‐PTMO). Blends of an unsaturated polyester (UPR, based on propylene glycol, terephthalic, and maleic acids) resin with different loading of itaconimide end‐capped telechelics were investigated for their mechanical and thermal properties. Blending with these additives enhanced the mechanical and thermal properties of the crosslinked UPR. The impact strength and fracture toughness values were improved by more than 100% by small quantities of the additives. The improvement in fracture properties was correlatable primarily to a decrease in overall crosslink density. The distribution of the polyether chains in the cured matrix as dictated by the reactivity ratios of styrene and polyether macromer was found to have a role in deciding the properties. The properties were found to be the best for the blend toughened with I‐PPG with a molecular weight 2000 g/mole at a loading of 2.5 parts per hundred parts. On comparison with the resin blended with a maleimide‐encapped polyether of same molecular weight, the itaconimide end‐capped polyether was found to provide a better toughening of the UPR matrix. This could a priori be explained based on a difference in distribution of the end‐capped polyether as a consequence of the difference in the copolymerization behavior of itaconimide and maleimide functionalized telechelics toward UPR. The itaconimide enters into a random copolymerization with styrene and the probability for formation of the continuous sequences of the itaconic group is about 60%. This will permit polyether segments to come close enough to form micro or even sub‐micron clusters of the polyether which eventually forms the micro crystallites of poly ether that act as a crack stopper. This possibility cannot be envisaged in maleimides which forms invariably an alternating sequence with styrene. The morphological features as reflected in scanning electron microscopic analyses tallied with these observations. This work could help identify the ways for obviating the inherent brittleness of the UPR systems.

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Toughening of a polytriazole resin with diprogargyl poly(propylene glycol)s

Hao²,

Zhang

et al. 2022

Polymer Engineering & Sci

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The rapid development of aerospace technology has put demands on the high tough thermosetting resins. Polytriazole (PTA) resins are a kind of high performance thermosetting resins as matrices of structural composites for aerospace parts. It is necessary to develop polytriazole resins with high toughness. In this paper, propargyl-terminated polypropylene glycols (P t PGs) with various molecular weights (P t PG400, P t PG600, P t PG725) were synthesized and characterized. A series of P t PG-toughened polytriazole (PPTA) resins were prepared by the "Click" reaction of P t PG and N,N,N 0 ,N 0 -tetrapropargyl-4,4 0 -diaminodiphenylmethane (TPDDM) with 1,1-bisazidomethyl-4,4 0 -biphenyl (BAMBP). The curing behavior of the PPTA resins and the thermal, mechanical, as well as water absorption of the cured PPTA resins were investigated. The results show that the PPTA resins have excellent processing properties and can be cured and molded at 80 C. The molecular weight and the amount of P t PG have a significant influence on the mechanical properties of PPTA resins. When P t PG600 with the molar ratio of alkyne groups 1.0% is formulated, the impact strength of the cured PPTA-600-1.0 resin reaches 63.6 ± 8.2 kJÁm À2 and K IC 2.57 MPaÁm À1/2 , which are 57.4% and 41.2% higher than those of PTA resin respectively. The glass transition temperature (T g ) and water absorption of the cured PPTA-600-1.0 resin are 223.8 C and 0.22% respectively. K E Y W O R D Shigh performance resin for advanced composite, polytriazole resin, propargyl-terminated polypropylene glycol, toughened polytriazole resins, toughening of thermosetting resin

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Maleimide end- capped polyether telechelics as novel toughening agents for unsaturated polyester resin

Cited by 13 publications

References 39 publications

On the toughening of unsaturated polyester resins using nadimide end‐functionalized polyether telechelics

On the toughening of unsaturated polyester resins using nadimide end‐functionalized polyether telechelics

Itaconimide telechelics of polyethers, synthesis, and their impact on mechanical properties of unsaturated polyester resins

Toughening of a polytriazole resin with diprogargyl poly(propylene glycol)s

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