Synthesis of isoeugenol biobased epoxy polymer by forming α‐hydroxyl ester and degradation studies

Abstract

The synthesis of bio‐based monomers and polymers from renewable feedstock, such as plant biomass, is desirable because of the depletion of fossil fuel resources and the reliance of thermosetting epoxy resin on non‐renewable petrochemical monomers. Despite the excellent polymeric properties of bisphenol‐based epoxy resins, these negatively impact human health. Herein, the synthesis of self‐curable epoxy polymers from the bio‐based material isoeugenol by forming α‐hydroxyl esters is reported. The epoxides are named AB (single epoxide and ester groups) and A2B2 (double epoxide and ester groups), based on the number of active ester and epoxide groups. The materials derived from the bio‐based material, AB and A2B2, were initiated with and without the catalyst N,N′‐dimethylaminopyridine (DMAP) and curing agent diaminodiphenylmethane. Without the catalyst, AB and A2B2 self‐polymerized at 247 and 210°C, respectively. Notably, the polymerization temperatures for AB and A2B2 decreased after the addition of DMAP. The self‐cured epoxy resin without the catalyst showed the highest thermal stability and glass transition temperature (Tg = 156°C). Degradation and recovery studies suggested forward that 51% of the material could be recovered and 94% of the polymer could be degraded from the self‐cured A2B2 in 25 wt% NaOH solution.

Biobased Low-k Polymers at High Frequency Derived from Isoeugenol

“…Cured M1, cured M2, and cured B1 show the similar 5 wt % weight loss temperatures (T 5d ) of 474, 473, and 473 °C, respectively. Such results are superior to those of the reported isoeugenol-based epoxy resins (T 5d = 201−322 °C), 34,37,53 commercial epoxy resins (DGEBA epoxy resin cured by DDM, T 5d = 321 °C), 52 and the reported benzocyclobutene resins derived from biomass (T 5d = 400−460 °C). 28,46,55−57 The thermal dimensional stability of materials is another crucial parameter for the practical application of highperformance polymers.…”

“…Besides this, the three polymers display excellent mechanical properties with a high storage modulus of 2.8, 2.3 and 2.1 GPa at room temperature, respectively (Figure ). These results demonstrate that cured M1 and cured B1 display excellent thermal stability, which is superior to those of isoeugenol-based epoxy resins previously reported ( T g = 105–165 °C) ,, and the commercial DGEBA epoxy resin (cured by diaminodiphenylmethane (DDM), T g = 189 °C) …”

“…Structurally, isoeugenol, containing cross-linkable propylene and functional hydroxyl groups, is an ideal precursor for the preparation of the high-performance polymers. Nevertheless, there are a few reports on the conversion of isoeugenol to high-performance thermosets instead focusing on the application of isoeugenol in antibacterial materials like food packaging due to its antibacterial properties , or the conversion of isoeugenol into vanillin in the industry. , Some investigations have paid attention to convert isoeugenol to epoxy, − benzoxazine resins, , and renewable polyesters . However, methoxy groups belonging to isoeugenol still remain in the backbones of polymers that may deteriorate the hydrophobicity and lead to high D k and D f values, which is unfavorable for low- k materials .…”

Sustainable Vanillin-Based Epoxy Resin with Excellent Flame Retardancy and Mechanical Properties

“…It is attributed to that the rigid large π–π conjugated Schiff base structure between the Schiff base and adjacent benzene ring, and the cross-linking reaction between the Schiff base and epoxide groups forms more cross-linking points, further hindering the mobility of molecular chains. Figure c displays the comparison of E ′ and T g for VH-HDA-EP/DDM with other bio-based epoxy resins reported in several literature studies. ,,,,,− Interestingly, the T g value of VH-HDA-EP/DDM is the highest among these reported results, which indicates the excellent heat resistance. It can be seen that E ′ shows a sharp decreasing trend within the maximum range of tan delta curves, which is called relaxation, and it is attributed to glass transition .…”