Surface Science and Adhesion in Cosmetics. Группа авторов

-0.1 ± 1.3 13.7 ± 7.6 hydrated 31.5 ± 6.0 33.4 ± 3.8 -1.9 ± 4.9 -0.2 ± 0.6 15.0 ± 8.2 abraded 32.9 ± 4.8 37.0 ± 4.0 -4.0 ± 5.4 -0.1 ± 1.4 15.4 ± 9.2

Table 3.7 Monomers effect on the gel fraction (GF), surface gloss (G) and micro-hardness (HV) of the UV cured cross-linked coatings. Monomers 1-TBCHA, 7-HPMA and 8-HPMA fall into the ɛ_β (elongation at break) range of 20-50% so that they exhibit reduced brittleness. AGF=GF₀ (is after 72 hours of storage) –GF (is immediately after cure).

Monomer		Conc.	Gel fraction			Surface gloss			Microhardness
			GF	GF0	AGF*/GF0 x 100	G	G0	AG**/G0 x 100	HV	HV0	AHV***/HV0 x 100
		%	%	%	%	GU	GU	%	MPa	MPa	%
1	TBCHA	30	97,4	98,0	0,61	46	68	32	104	144	38
2	TBCHA	40	94,0	94,1	0,11	51	72	29	69	83	20
3	EGDMA	30	98,5	99,3	0,81	47	59	20	204	281	38
4	EGDMA	40	96,4	98,9	2,53	47	57	18	220	314	43
5	THFA	30	96,0	96,3	0,31	59	73	19	25	47	88
6	THFA	40	95,7	96,7	1,03	54	61	11	28	32	14
7	HPMA	30	97,0	97,6	0,61	50	63	21	99	151	53
8	HPMA	40	95,0	99,9	4,90	43	58	26	65	134	106

      * AGF = (GF₀ – GF)

      ** AG = (G₀ – G)

      *** AHV = (HV_Q – HV)

      **** Characteristics in bold are in required range of close to that

Figure 3.17 Elastic modulus (E)and (%) elongation at break (ɛ_B) values for the coatings with 30% and 40% of monomers measured immediately after cure (0) and after 3 days of storage.

They also found that the human nail at 55% relative humidity has a Young’s modulus of 2.32 GPa. Systems containing TBCHA that they tested showed the most stable E values with the post-cure having no effect on the post-cured coatings. So, for the natural nail the coating should have at least an ɛ_B (elongation at break) value of 0.6%. As can be seen in Figure 3.17 TBCHA