Hydrogen Bonding-Rich Bio-Benzoxazine Resin Provides High-Performance Thermosets and Ultrahigh-Performance Composites

Producing thermosetting polymers using natural renewable resources has attracted great attention due to the requirement of sustainable development for human beings. Herein, we represent our design of a novel biobased thermosetting resin (KAE-fa) containing a polymerizable oxazine ring and a furan group derived from renewable kaempferol and furfurylamine. The distinctive presence of rich intra- and intermolecular hydrogen bonds within KAE-fa imparts it with thermal latent polymerization characteristic, long shelf life, and exceptional high performance of its resulting polybenzoxazine. Notably, the resulting thermoset, poly(KAE-fa), demonstrates a substantially high glass transition temperature (Tg) of 304 °C, an impressively elevated char yield (in N2) of 63%, and an extraordinarily low heat release capacity of 10.12 J·g-1·K-1. In addition, KAE-fa has also been utilized to fabricate a carbon fiber-reinforced composite [CF/poly(KAE-fa)]. Employing this newly obtained high-performance bioresin as the matrix, CF/poly(KAE-fa) exhibits a remarkable property enhancement. For instance, CF/poly(KAE-fa) shows 108, 28, and 82.7% increases in Tg, tensile strength, and Young’s modules (room temperature), respectively, compared with the carbon fiber-reinforced BA-a composite [CF/poly(BA-a)]. These advantages underscore the great potential of using renewable bioresins for developing both high-performance thermosets and composites with key applications spanning from transportation to aerospace.</p

The average latencies of fixation on a new object and average number of trials in which onsets were fixated in the non-onset target condition of Experiment 1.

<p>The average latencies of fixation on a new object and average number of trials in which onsets were fixated in the non-onset target condition of Experiment 1.</p

Fixation results in the non-onset target condition of Experiment 1.

<p>Panel A illustrates the probability of fixating new objects under the non-onset target condition in Experiment 1; Panel B illustrates the probability of first look to onset for the three mask types under the non-onset target condition in Experiment 1.</p

The mean accuracy of the three mask conditions in Experiment 2.

<p>The mean accuracy of the three mask conditions in Experiment 2.</p

Chronotype classifications, and descriptive statistics by chronotype.

†<p>See Methods section for gender differences.</p>‡<p>Mean (standard deviation). *p≤.05; **p≤.01.</p

Mediation analyses for chronotype, daydream frequency, mind wandering, sleep quality and positive affect.

†<p>Taking account of the difference between the initial and the mean indirect effect estimates.</p><p>*p≤.05;</p><p>**p≤.01;</p><p>***p≤.0005.</p

Paths of mediation analysis.

<p>Paths of mediation analysis.</p

The sequence of events of two trials in Experiment 1.

<p>The target letter “H” or “S” can be either an onset target or a non-onset target.</p

The average latencies of fixation on a new object and average number of trials in which onsets were fixated for all conditions in Experiment 2.

<p>The average latencies of fixation on a new object and average number of trials in which onsets were fixated for all conditions in Experiment 2.</p

Descriptive statistics for each PSQI component for each study.

†<p>Pearson, two-tailed.</p><p>*p≤.05;</p><p>**p≤.01;</p><p>***p≤.0005.</p>‡<p>Clock times; sd in minutes.</p