Synthesis of a novel UV-curable prepolymer 1,3-bis[(3-ethyl-3-methoxyoxetane)propyl]tetramethyldisiloxane and study on its UV-curing properties

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Fig. 12

Fig. 13

Fig. 14

Analytical table of the 1H-NMR spectrum for the 3-ethyl-3-allylmethoxyoxetane_

Location of H	Chemical shift/(δ/ppm)	Structural formula
1	0.86	3H, -CH3
2	1.73	2H, -CH2-
3	3.53	2H, -CH2-
4	3.97	2H, -CH2-
5	5.87	H, -CH=
6	5.24	2H, =CH2
7	4.36	2H, -CH2-
8	4.42	2H, -CH2-

Mechanical property test results of the prepolymer UV-cured samples_

Numbering	Tensile strength /MPa	Elastic modulus /MPa	Elongation at break /%
1	26.28	3,028.72	4.13
2	23.99	2,831.19	3.89
3	22.97	2,730.26	4.23
4	27.90	3,195.19	3.96
5	28.62	2,890.40	4.26
Average value	25.95	2,935.15	4.09
Standard deviation	2.19	161.97	0.15

Mechanical property test results of the 2021p UV-cured samples_

Numbering	Tensile strength/MPa	Elastic modulus/MPa	Elongation at break/%
1	32.11	3,165.01	2.63
2	24.17	3,454.75	2.58
3	34.87	2,719.27	2.13
4	26.26	3,012.03	2.67
5	25.76	2,855.39	2.08
Average value	28.63	3,041.29	2.42
Standard deviation	4.60	285.21	0.29

Materials and reagents_

Materials and reagents	Purity (%)	Manufacturer
Diethyl carbonate	99.7	Sinopharm Chemical Reagent Co., Ltd
Trihydroxypropane	99.7	Sinopharm Chemical Reagent Co., Ltd
Anhydrous magnesium sulfate (solid)		Sinopharm Chemical Reagent Co., Ltd
Potassium hydroxide (solid)		Tianjin Damao Chemical Reagent Factory
Allyl bromide	99.7	Tianjin Damao Chemical Reagent Factory
Toluene	99.9	Xilong Chemical Co., Ltd
Dichloromethane	99.7	Xilong Chemical Co., Ltd
Tetrabutylammonium bromide	99.7	Xilong Chemical Co., Ltd
Triarylsulfonium hexafluoroantimonate (UV-6976)	99.7	Dow Union Carbide
1,1,3,3-tetramethyldisiloxane	99	Shanghai Chuqing New Material Co., Ltd.
Karstedt catalyst	99.5	Shanghai Aladdin Technology Co., Ltd.
E-51 epoxy resin	98	Shanghai Resin Factory
2021p alicyclic epoxy resin	98	Daicel (China) Investment Co., Ltd

Analytical table of the 1H-NMR spectrum for the 3-ethyl-3-hydroxymethyloxetane_

Location of H	Chemical shift /(δ/ppm)	Structural formula
1	0.77	3H, -CH3
2	1.60	2H, -CH2-
3	3.58	2H, -CH2-
4	3.74	H, -OH
5	4.28	2H, -CH2-
6	4.33	2H, -CH2-

Mechanical property test results of the E-51 UV-cured samples_

Numbering	Tensile strength/MPa	Elastic modulus/MPa	Elongation at break/%
1	20.75	2,224.11	5.83
2	19.60	1,912.03	6.12
3	21.03	2,329.58	4.76
4	20.57	2,168.32	4.92
5	18.44	1,895.36	5.43
Average value	20.08	2,105.88	5.41
Standard deviation	1.06	193.53	0.58

Analytical table of the 1H-NMR spectrum for the 1,1,3,3-tetramethyldisiloxane_

Location of H	Chemical shift/(δ/ppm)	Structural formula
1	0.17	12H, -CH3
2	4.66	2H, -Si-H

Analytical table of the 1H-NMR spectrum for the prepolymer_

Location of H	Chemical shift/(δ/ppm)	Structural formula
1	0.02	12H, -CH3
2	0.47	4H, -CH2-
3	1.55	4H, -CH2-
4	3.37	4H, -CH2-
5	3.49	4H, -CH2-
6	1.70	4H, -CH2-
7	0.85	6H, -CH3
8	4.35	4H, -CH2-
9	4.41	4H, -CH2-