Infrared quantification of binary rubber blends with overlapping bands

BARROS, ALEXANDRA HELENA DE; MURAKAMI, LIDIA M.S.; MAGALHÃES, RACHEL F.; TAKEMATSU, MARCIA M.; DINIZ, MILTON F.; SANCHES, NATÁLIA B.; DUTRA, JORGE CARLOS N.; DUTRA, RITA DE CÁSSIA L.

doi:10.1590/0001-3765202320220289

ALEXANDRA HELENA DE BARROS

Conceptualization, Methodology, Investigation, Writing – Original Draft

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0001-9063-2885

LIDIA M.S. MURAKAMI

Investigation, Resources

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0003-2589-7769

RACHEL F. MAGALHÃES

Investigation, Writing – Original Draft, Supervision

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0002-1364-3748

MARCIA M. TAKEMATSU

Investigation, Writing – Review and Editing, Supervision

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0001-9323-3898

MILTON F. DINIZ

Methodology

Instituto de Aeronáutica e Espaço (IAE), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Divisão de Propulsão, Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0003-0246-0660

NATÁLIA B. SANCHES

Writing – Original Draft, Writing – Review and Editing, Supervision

Centro Universitário Sant’Anna (UNISANT’ANNA), Rua Voluntários da Pátria, 257, Santana, 02011-000 São Paulo, SP, Brazil

http://orcid.org/0000-0002-3545-119X

JORGE CARLOS N. DUTRA

Supervision

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0002-0923-620X

RITA DE CÁSSIA L. DUTRA

Conceptualization, Methodology, Writing – Original Draft, Writing – Review and Editing, Funding Acquisition, Supervision

Instituto Tecnológico de Aeronáutica (ITA), Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Praça Marechal Eduardo Gomes, 50, Vila das Acácias, 12228-900 São José dos Campos, SP, Brazil

http://orcid.org/0000-0001-9958-1279

Correspondence to: Rita de Cássia Lazzarini Dutra E-mail: ritacld@ita.br

Components	Content (mass %)
EPDM Keltan 6950 (ET: 48% e ENB: 7.5%)	5.1 ; 15.4 ; 25.7 ; 36.0 ; 46.3
Polybutadiene (Buna CB 45B)	46.3 ; 36.0 ; 25.7 ; 15.4 ; 5.1
Naphthenic Oil NH-140 (plasticizer)	10.3
Carbon black N550 (charge)	30.8
Zinc oxide (activator)	3.1
Stearic Acid	1.0
Dispersion additive	1.0
Sulfur (vulcanizing agent)	1.5
TMTD (accelerator)	0.8

Rubber	Wavenumber (cm^-1)	Functional group	Vibrational mode
EPDM	887	RR´CCH₂	Wagging
	910	C=C vinyl
	966	C=C trans
	993	C=C vinyl
	1376	CH₃	Symmetric angular bending
BR	743	C=C cis	Wagging
	909	C=C vinyl
	966	C=C trans
	992	C=C vinyl

EPDM/BR (relative content)	A₈₈₇/A₇₄₃	Parameters
10/90 (0.11)	2.000	$\hat{μ}$ = 1.833
	2.000	R = 0.565
	1.435	$\hat{σ}$ = 0.243
	1.500	${\hat{σ}}_{\hat{μ}}$ = 0.109
	1.833	RD = 5.95 %
30/70 (0.43)	3.600	$\hat{μ}$ = 3.739
	3.143	R = 1.757
	4.214	$\hat{σ}$ = 0.755
	3.739	${\hat{σ}}_{\hat{μ}}$ = 0.338
	4.900	RD = 9.04 %
50/50 (1)	6.333	$\hat{μ}$ = 7.571
	5.533	R = 3.550
	9.083	$\hat{σ}$ = 1.526
	7.571	${\hat{σ}}_{\hat{μ}}$ = 0.682
	8.923	RD = 9.00 %
70/30 (2.33)	24.111	$\hat{μ}$ = 24.111
	35.500	R = 15.125
	22.375	$\hat{σ}$ = 6.504
	30.600	${\hat{σ}}_{\hat{μ}}$ = 2.909
	20.375	RD = 12.06 %
90/10 (9)	76.000	$\hat{μ}$ = 67.667
	54.000	R = 45.333
	62.667	$\hat{σ}$ = 19.493
	67.667	${\hat{σ}}_{\hat{μ}}$ = 8.718
	99.333	RD = 12.88 %

Band intensity ratio	R (linearity)	R² (results percentage explained by the methodology)	Methodology error (%)	Methodology error comment
A ₈₈₇ /A ₇₄₃	0.995	98	9.04	High error if compared to the equipment precision limit ³⁹ (band intensity measure variation) ≤ 2%. which is mainly obtained under thickness control ideal conditions (transmission/solution/cell with spacer). This error of around 9% may be due to the weak intensity of the band at 743 cm^-1, which makes it difficult to properly measure BR contents. However, the band in 743 cm^-1 was evaluated for having no overlapping with EPDM bands.
A ₁₃₇₆ / A ₇₄₃	0.996	99	8.06	This error of around 8% may also be due to the band intensity at 743 cm^-1, considered weak, which makes it difficult to measure BR contents. However, it was evaluated for having no overlapping with EPDM bands.
A ₈₈₇ /A ₉₀₉	0.947	90	2.47	Error considered satisfactory if compared to equipment precision limit ³⁹ (band intensity measure variation) ≤ 2%, but this band in 909 cm^-1 overlaps with the EPDM characteristic band.
A ₈₈₇ /A ₉₆₆	0.91	83	5.35	Since this band shows overlapping at 966 cm^-1, with EPDM characteristics, the error is considered satisfactory under the conditions of the conducted analysis.
A ₈₈₇ /A ₉₉₀	0.900	81	3.67	Since this band shows overlapping at 990 cm^-1, with EPDM characteristics, the error is considered satisfactory under the conditions of the conducted analysis.

SAMPLE EPDM/BR	A₈₈₇ (EPDM)	A₇₄₃ (BR)	A₈₈₇/A₇₄₃	A₈₈₇/A₇₄₃ Median	Mean Standard Deviation	Relative Deviation (%)	EPDM Content (%)	BR Content (%)
SAMPLE A Nominal content: (30/70) - Transmission data	0.046	0.012	3.883	3.833	0.330	8.60	20.83	79.17
	0.037	0.008	4.625
	0.032	0.011	2.909
	0.047	0.016	2.937
	0.071	0,016	4.437
SAMPLE B Nominal content: (10/90) – Transmission data	0.042	0.013	3.230	2.737	0.162	5.92	10.40	89.60
	0.052	0.019	2.737
	0.066	0.026	2.538
	0.075	0.024	3.125
	0.043	0.018	2.389
SAMPLE B Nominal Content: (10/90) – UATR data	0.013	0.006	2.166	2.166	0.064	2.95	15	85
	0.013	0.006	2.166
	0.013	0.006	2.166
	0.012	0.006	2.000
	0.011	0.006	1.833

[1] Correspondence to: Rita de Cássia Lazzarini Dutra E-mail: ritacld@ita.br

Brasil

Brasil

Infrared quantification of binary rubber blends with overlapping bands

Abstract