Table 3.

Solid-state ¹³C NMR assignment and quantitative analysis of chemical groups for cured 20%BPF and PF during UV weathering.

Chemical Group Structure	Chemical Shirt (ppm)	Calculation
		20%BPF					PF
		0	120	240	480	960	0	120	240	480	960
C=O form aldehydes/ketones	220–200	0.98	1.08	1.11	1.19	1.24	0.85	1.10	1.26	1.37	1.32
C=O from carboxylic acids	186–176	0.09	0.14	0.23	0.26	0.30	0.02	0.02	0.03	0.12	0.18
C=O from esters	176–168	0.05	0.05	0.12	0.17	0.16	0.01	0.01	0.02	0.09	0.14
Phenolic carbon	160–148	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
Substituted ortho and para aromatic carbons	137–123	4.19	4.52	4.29	4.26	4.20	4.21	4.43	4.31	4.22	4.07
Dimethylene ether bridges	75–65	0.56	0.68	0.71	0.50	0.48	0.20	0.46	0.26	0.18	0.24
Methylol groups	63–58	0.32	0.54	0.43	0.33	0.27	0.19	0.36	0.25	0.20	0.23
Benzylamines	58–45	0.53	0.88	0.91	1.11	1.20	0.56	1.06	0.89	0.96	0.74
Methylene bridges	45–29	2.27	2.40	2.36	2.27	2.10	2.17	2.38	2.29	2.16	2.03