Alvo de Detecção
Determinação do teor de dimeticona
Visão geral
O óleo de silicone dimetílico é um novo material polimérico sintético, incolor e transparente. Está disponível em uma ampla gama de viscosidades (de 5 cps a 8 milhões de cps), desde líquidos altamente fluidos até substâncias semissólidas espessas. Apresenta propriedades únicas, como suavidade, maciez e repelência à água, além de boa estabilidade química, excelente isolamento elétrico e resistência a altas e baixas temperaturas. Possui alto ponto de fulgor, baixo ponto de congelamento e pode ser usado continuamente em uma faixa de temperatura de -50 °C a +200 °C. Adicionalmente, apresenta um pequeno coeficiente de viscosidade-temperatura, alta compressibilidade, baixa tensão superficial, repelência à água e resistência à umidade eficazes, bem como baixo calor específico e condutividade térmica.
Graças às suas características excepcionais, o óleo de silicone dimetílico tem obtido ampla aplicação em diversos setores, incluindo produção industrial e agrícola, defesa nacional, pesquisa científica e saúde. É amplamente utilizado para isolamento elétrico, desmoldagem, antiespumante, amortecimento, absorção de choques, laminação, prevenção de poeira, impermeabilização e controle de umidade em ambientes com alta e baixa umidade. Princípio: Um solvente orgânico apropriado é utilizado para enxaguar ou imergir a amostra de teste, transferindo o óleo de silicone para sua superfície. Utilizando a banda de absorção característica no espectro infravermelho da dimeticona como comprimento de onda de medição, é possível obter boa exatidão e precisão.
Aparelho
Espectrômetro HKL-FTIR dedicado à dimeticona
Requisitos do instrumento
A precisão do número de onda deve estar dentro de ±5 cm-1perto de 3000 cm-1e ±1 cm-1perto de 1000 cm-1O instrumento deve ser calibrado usando um filme de poliestireno (com aproximadamente 0,04 mm de espessura) e seu espectro deve ser registrado.
(1)Precisão do número de onda
Número de onda de calibração | 3027 cm-1 | 2851 cm-1 | 1601 cm-1 | 1028 cm-1 | 907 cm-1 |
Número de onda medido | 3025,76 cm-1 | 2850,27 cm-1 | 1600,63 cm-1 | 1027,87 cm-1 | 906,38 cm-1 |
Desvio Permitido | 5 cm-1 | 5 cm-1 | 1 cm-1 | 1 cm-1 | 1 cm-1 |
Desvio real | 1,24 cm-1 | 0,73 cm-1 | 0,37 cm-1 | 0,13 cm-1 | 0,62 cm-1 |
Conformidade | Sim | Sim | Sim | Sim | Sim |
(2) Resolução
Categoria | Resolução máxima (3110–2850 cm-1) | Resolução de profundidade (2851–2870 cm)-1) | Resolução de profundidade (1583–1589 cm)-1) | Resolução Nominal |
Exigência | 7 picos | ≥18% | ≥12% | 2 cm-1 |
Desempenho mensurado | 7 picos | 25% | 18% | 1,5 cm-1 |
Conformidade | Sim | Sim | Sim | Sim |
Solução
Attenuated Total Reflection (ATR) Method — Determination of Dimethicone Content
Procedure
Perform infrared spectral scanning of both the sample and reference standard using ATR-FTIR within the wavenumber range of 4000–700 cm-1.
Measure the absorbance at 1259 cm-1 (peak height method).
Calculate the polydimethylsiloxane (PDMS) content in dimethicone using the following formula:
PDMS Content%=100×(Au/As)×(Ds/Du)
Where:
Au= Absorbance of the sample
As= Absorbance of the reference standard
Du= Relative density of the sample at 25°C
Ds= Relative density of the reference standard at 25°C
Application
Applications in the Electromechanical Industry
Dimethyl silicone oil is widely used in motors, electrical appliances, and electronic instruments as a high-temperature-resistant, arc- and corona-resistant, anti-corrosive, moisture-proof, and dust-proof insulating medium. It is also utilized as an impregnating agent for transformers, capacitors, and television scanning transformers. In various precision machinery, instruments, and meters, it serves as a liquid shock-absorbing and damping material. The vibration-damping properties of dimethyl silicone oil are minimally affected by temperature, making it suitable for instruments operating under strong mechanical vibrations and significant environmental temperature fluctuations, such as those in aircraft and automobiles. It is used to stabilize instrument readings, dampen vibrations, and even as a liquid spring in aircraft landing gear.
As a Defoamer
Due to its low surface tension, insolubility in water, and high-boiling-point mineral oils, as well as its chemical stability and non-toxicity, dimethyl silicone oil is widely used as a defoamer in industries such as petroleum, chemical processing, pharmaceuticals, food processing, textiles, printing, dyeing, and papermaking. A concentration of just 10-100 ppm provides an effective defoaming effect.
As a Release Agent
Thanks to its non-stick properties with rubber, plastics, and metals, it is used as a release agent in the molding of rubber and plastic products, as well as in precision casting. It not only facilitates easy demolding but also ensures clean, smooth, and finely textured surfaces on finished products.
As an Insulating, Dust-Proof, and Anti-Mold Coating
When applied to glass or ceramic surfaces and heat-treated at 250-300°C, dimethyl silicone oil forms a semi-permanent waterproof, anti-mold, and insulating film. Treating insulating components with it enhances their insulation properties; applying it to optical instruments prevents lens and prism mold growth; coating medicine bottles extends shelf life and prevents drug adhesion and loss; and treating film surfaces reduces friction, prolonging film longevity.
As a Lubricant
It is suitable for lubricating rubber and plastic bearings and gears. It can also serve as a high-temperature lubricant for steel-on-steel or steel-on-other-metal rolling friction. However, due to its relatively poor lubrication performance at room temperature, it is generally not recommended for ordinary metal-on-metal lubrication.
As an Additive
Dimethyl silicone oil can be added to various materials to enhance their properties. For example, adding a small amount to paint prevents floating and wrinkling while improving gloss; incorporating it into ink enhances print quality; and mixing it into polishing wax (e.g., car wax) increases shine, protects the paint film, and provides excellent waterproofing.
Applications in Healthcare
Dimethyl silicone oil is non-toxic to humans and not broken down by bodily fluids, making it widely applicable in healthcare. Its defoaming properties are utilized in oral anti-flatulence tablets and pulmonary edema defoaming aerosols. Adding silicone oil to ointments improves skin penetration and efficacy. Certain silicone oil-based ointments are effective for treating burns, dermatitis, and bedsores. Its anticoagulant properties allow it to coat blood storage containers, extending blood sample preservation time.
Other Applications
Dimethyl silicone oil has many other uses. For instance, its high flash point, odorlessness, transparency, and non-toxicity make it suitable as a heat transfer fluid in steel, glass, and ceramic industries, as well as in laboratory constant-temperature baths. Its excellent shear stability makes it ideal for hydraulic fluids, especially in aviation. Treating rayon spinnerets with it eliminates static electricity, improving fiber quality. Adding silicone oil to cosmetics enhances skin moisturization and protection, among other benefits.