“…Silica as filler particle has a much higher elasticity modulus. of CB loading on thermal aging resistance of SBR has been studied by Mostafa et al [43], where it was found that carbon black accelerates the oxygen uptake and acts as a catalyst for direct oxidation. The effect of silica on thermal oxidative degradation of SBR has been studied in [44].…”
“…Silica as filler particle has a much higher elasticity modulus. of CB loading on thermal aging resistance of SBR has been studied by Mostafa et al [43], where it was found that carbon black accelerates the oxygen uptake and acts as a catalyst for direct oxidation. The effect of silica on thermal oxidative degradation of SBR has been studied in [44].…”
“…With further aging, eg, when the thermoâoxidative time is more than 68 hours for SBR, the macromolecular structure experiences further degradation and recrosslinking. For the most part these are depolymerizationâreaction and chain branching, leading to crosslinked molecular structure, such as which is depolymerized into , where stands for the loss of hydrogen atom in the SBR's molecular structure. further combines with oxygen atom into polarity elements, such as hydroxyl ( ) and carbonyl ( ), which finally evolve into a kind of nonactive structure.…”
Polymer materials such as rubber and plastics are prone to aging induced degradation, especially thermo-oxidative aging. In this paper, terahertz time-domain spectroscopy was employed to investigate the aging process of styrene butadiene rubber by spectrally following the evolution of its dielectric permittivity in the terahertz frequency region during prolonged high-temperature, accelerated, continuous thermo-oxidative aging. The real and imaginary parts of the dielectric constant in the 0.1-0.8 THz frequency band were obtained and analyzed, and shown to be consistent with present theoretical understanding. The study revealed a close relationship between the evolution of the rubber's dielectric permittivity and the material's physical response to the terahertz electromagnetic radiation during thermo-oxidative aging, manifesting a strong correlation between quantitative changes of the dielectric permittivity and the degree of aging, which can be understood qualitatively in terms of dynamical structural changes at the molecular level.
K E Y W O R D Sterahertz, rubber, thermo-oxidative aging, dielectric permittivity
| I NT RODU CTI ONThe polymer material styrene butadiene rubber (SBR), also known as polystyrene-butadiene copolymer, is currently the most popular man-made commercial rubber, accounting for more than 40% of sales, among all synthetic rubber materials, including butadiene rubber, styrene-butadiene rubber, isoprene rubber, and many others. 1 SBR resembles closely natural rubber, possessing many advantageous properties, such as wear-resistance and heat-resistance, higher curing rate compared with natural rubber, and good compatibility with natural rubbers and various synthetic rubbers. 2 As such it is widely used in aerospace, electronics, and automotive industries, as well as in consumer products such as appliances, apparel, and sporting goods, among many others. [3][4][5] Rubber is apt to suffer from aging due to high temperature, illumination, oxidation, hydrolysis, biodegradation, salt spray, and other environmental factors, 6,7 which degrades its quality and characteristic over time, and shortens its useful lifetime. Although aging of rubber is a natural phenomenon which is ultimately unavoidable, the prevention and retardation of aging, and proactive life prediction of rubber have been active research topics for many years. [8][9][10][11][12][13][14][15][16] Owing to its plastic nature, there are inherently flaws in the molecular structure of rubber, making it easily susceptible to aging due to invasion of external oxygen atoms. SBR's macromolecular chain has a type of unsaturated double bond structure, which readily reacts with oxygen atoms under common ambient conditions. The whole process has three phases, including chain initiation, chain propagation, and chain termination, with the stable product of degradation and crosslink formed at last. Currently, among the detection technologies for prediction of rubber aging, online spectral inspection approaches are the most popular, including i...
“…Struktur dari carbon black ditentukan oleh bentuk dan derajat percabangan. Penggunaan carbon black sebagai bahan pengisi pada elastomer NBR akan menghasilkan vulkanisat dengan sifat mekanis baik (Jovanovic et al, 2009;Mostafa et al, 2009). Indrajati et al (2012) mempelajari pengaruh HAF/ SRF terhadap sifat karakteristik vulkanisasi, morfologi dan swelling vulkanisat NBR.…”
The aim of this research was to study the effect of vulcanization temperature on mechanical properties and curing kinetics of NBR composites. The composites were formulated by using two types of carbon black i.e. N-330 and N-774
ABSTRAKTujuan dari penelitian ini adalah mengetahui pengaruh suhu vulkanisasi terhadap sifat mekanis dan kinetika vulkanisasi komposit NBR. Formulasi komposit menggunakan dua macam carbon black yaitu N-330 dan N-774. Kinetika vulkanisasi ditentukan dengan alat Moving Die Rheometer, dimana proses vulkanisasi berlangsung dikaitkan dengan torsi dan waktu. Proses pembuatan vulkanisat menggunakan hydraulic press pada suhu 150ÂșC dan 160ÂșC. Sifat mekanis komposit NBR yang diamati adalah tegangan putus, perpanjangan putus, kekerasan dan kuat sobek. Kinetika vulkanisasi didekati dengan persamaan Arrhenius dikaitkan dengan mekanisme reaksi dan diasumsikan orde satu. Hasil penelitian menunjukkan bahwa kinetika vulkanisasi dapat didekati dengan persamaan dari data reometer. Surface area carbon black sangat kuat mempengaruhi sifat mekanis dan rate constant (k) dari komposit NBR. Carbon black N 330 merupakan bahan pengisi yang bersifat sebagai penguat dan memberikan sifat mekanis tertinggi dibandingkan carbon black jenis lainnya.Kata kunci: kinetika vulkanisasi, NBR, suhu, mekanis.
PENDAHULUANElastomer merupakan polimer bercabang dengan modulus elastisitas rendah dan kemampuan deformasi tinggi sehingga dimungkinkan memiliki penggunaan lebih luas. Acrylonitrile butadiene rubber (NBR) merupakan kopolimer dari akrilonitril dan butadiena diproses dengan cara kopolimerisasi emulsi. Beberapa sifat yang dimiliki NBR antara lain makin tinggi kadar akrilonitril maka ketahanan minyak, tegangan putus dan ketahanan kikis tinggi tetapi sifat pampat tetap (compression set) dan elastisitas menurun. NBR merupakan polimer sintetis mempunyai ketahanan minyak sangat baik tetapi sifat mekanisnya rendah. Hal ini disebabkan NBR bersifat non kristalin. Pada proses pembuatan produk karet dengan
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