Effect of increasing NCO/OH molar ratio on the physicomechanical and thermal properties of isocyanate terminated polyurethane prepolymer

Gogoi, Runumi; Alam, Mohammad Sarwar; Khandal, Rakesh Kumar

doi:10.14419/ijbas.v3i2.2416

Cited by 28 publications

(27 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The amount of small flocs as well as viscosity of the binder causes different flow behaviour in elapsed time. The more time elapsed, the more molecular weight of polimeric binder, the more viscous binder, the more viscous the slurry, the larger flocs that are formed, the more pseudoplastic the slurry [29], [22], [26]. This trend is shown significantly from the measurement of 10 minutes to 20 minutes.…”

Section: Resultsmentioning

confidence: 85%

“…In equation 6, N is rotational speed (rpm), Rc is radius of container (2,25 cm), Rb is radius of spindle (0,16 cm) and x is radius at which shear rate was being calculated (cm). As viscosity of pseudoplastic slurry is very sensitive toward shear rate, so the calculation was adjusted at In propellant slurry, after mixing, as time elapsed, polimerization reaction between hydroxyl groups of HTPB and isocyanate groups of TDI occurs and leads to form binder for solid contents as well as increase the viscosity of propellant slurry [22]. To investigate the effect of increasing viscosity on pseudoplasticity index, viscosity of propellant slurry is measured at 10, 20, 30, 40 minutes after mixing at various shear rates below 1 s -1 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

Restasari

Budi

Hartaya

2018

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Abstract. The modification of the percentage of aluminium is necessary to obtain certain specific impulse. But, it affects the pseudoplasticity of propellant in elapsed time that is important in casting. Therefore, this research attempts to investigate the pseudoplasticity of propellant slurry with varied aluminium contents and as time elapsed, the range of percentage of aluminium and time that allows propellant slurry to be well processed. The methods include measuring the viscosity of propellant slurries that contain 6, 8, 10, 12, 14, 16 and 18% of aluminium at varied shear rates until 40 minutes after mixing by using Brookfield viscometer. The graphs of viscosity versus shear rate were made to determine pseudoplasticity index. After that, the graph volume fraction versus pseudoplasticity index were made to be investigated. It is concluded that the more aluminium contents, the slurries with 6 to 12% aluminium contents exhibit more pseudoplastic behaviour, but the slurries with 12 to 16% aluminium exhibit less pseudoplastic. While, slurry of 18% aluminium exhibit high pseudoplasticity. In the correlation with the time, the slurry compositions of 6, 8, 14, 16% aluminium become more pseudoplastic as time elapsed. While, for compositions of 10, 12 and 18% aluminium, the trend becomes contrary. Based on the pseudoplasticity index, propellant slurries that contain 10 and 14% of aluminium are suitable for pressure casting. While for slurries with 6, 8 and 16% of aluminium are also suitable for vacuum casting. All of those suitability are possesed until 40 minutes after mixing. While, the composition of slurries that contain 12 and 18% of aluminium need to be modified to enhanced its castability.

show abstract

Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

Restasari

Budi

Hartaya

2018

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…The sample was prepared in duplicate by dissolving in tetra hydrofuran (THF) and dimethy formamide (DMF) in the ratio of 1 : 3, and used as mobile phase at a flow rate of 1 ml/min for elution purposes. The molecular weights were calibrated with polystyrene as standards 11 whereas inherent viscosity of PGCL copolymer was measured in 1,1,1,3,3,3-hexafluoroisopropanol with a concentration of 0.1d l/g at 25C using Ubblehode viscometer.…”

Section: Methodsmentioning

confidence: 99%

Controlled Hydrolytic Degradation of Polyglycolide–Caprolactone-Based Bioabsorbable Copolymer

Singh

Tyagi

2017

Current Science

View full text Add to dashboard Cite

Polyglycolide-caprolactone (PGCL)-based copolymer was synthesized from glycolide and caprolactone by ring opening polymerization in the presence of stannous octoate catalyst and diethylene glycol initiator. The effects of prepolymerization time, monomer ratio, monomer-to-catalyst and monomer-to-initiator ratios on per cent weight conversion were optimized. The end-capped copolymer was synthesized to make absorbable sutures having controlled bioabsorbability at different pH levels. It was observed that endcapped absorbable copolymer was more stable at pH 10.0 compared to uncapped absorbable material. End-capped copolymer also retained higher tensile strength compared to uncapped copolymer after 21 days. This phenomenon of controlled hydrolytic degradation of PGCL-based bioabsorbable polymer having terminal group end-capping can be attributed to less availability of hydrophilic end groups facilitating hydrolytic degradation of polymers.

show abstract

“…Dalam arti lain, slurry semakin sulit untuk mengalir. Hal ini disebabkan oleh semakin besarnya matriks poliuretan yang terbentuk dari HTPB dan TDI, seperti dijelaskan pada Gambar 1-1 (Gogoi, Alam, & Khandal, 2014;K et al, 2010). Selanjutnya, untuk mendapatkan persamaan (1-3), grafik ln viskositas vs waktu tersajii pada Gambar 3-2.…”

Section: Gambarunclassified

Pengaruh Komposisi Ap Terhadap Prosesibilitas Slurry Propelan Dengan Kandungan Aluminium Tinggi (Effects of Ammonium Perchlorate Composition on High Content Aluminium Propellant Slurry)

Restasari¹,

Budi²,

Hartaya³

2018

Jutekgan

View full text Add to dashboard Cite

As propellant solid contents, Ammonium perchlorate (AP) affect the fluid characteristics of propellant slurry that are important in mixing and casting process to produce homogenous solid propellant. Therefore, this research aims to find out the effects of Ammonium perchlorate compositions (fine AP (APh) : coarse AP(APk)) on the slurry`s fluid characteristics which are viscosity, pot life, and pseudoplasticity index. In this research, propellant A (APh : APk 1:2), propellant B (APh : APk 1:1), propellant C (APh : APk 3:2), and propellant D (APh : APk 2:1) were made. The methods include the measurement of viscosity by using Brookfield RVT viscometer spindle 07 at 0,3 rpm every 15 minutes. While, at 35th minute, the viscosity at 0,3; 0,5 and 0,6 rpm were measured. Based on the data of viscosity, graphs of ln viscosity vs time as well as viscosity vs shear rate were made to determine the equations of viscosity build-up and Power Law. It is known that the initial viscosity of propellants are 11,493 – 52945 P. The lowest viscosity and pot life (13,12 minutes) are shown by propellant A. While, pseudoplasticity index of propellants are 0,655 – 0,991. The lowest point is shown by propellant D and the highest point is shown by propellant B. Based on this index, propellant A is not suitable to be casted in vacuum. On the other hand, propellant C is relatively suitable to be improved because its viscosity (17,506 P) and rate of increasing viscosity (247 P/minute) are not much different from propellant A. In addition, its pseudoplasticity index (0,972) is suitable for vacuum casting. The conclusion is that the correlation between APh : APk and fluid characteristics of of propellant slurry (viscosity, pot life and pseudoplasticity are various because of packing factor of particles in propellant composition. AbstrakSebagai padatan pengisi propelan, Ammonium perklorat (AP) dapat mempengaruhi sifat fluida dari slurry propelan yang penting dalam pencetakan untuk menghasilkan propelan yang homogen. Oleh karena itu, penelitian ini bertujuan untuk menemukan pengaruh komposisi AP (AP halus (APh): AP kasar(APk)) terhadap sifat fluida slurry yang meliputi viskositas, pot life dan indeks pseudoplastisitas. Dalam penelitian ini, dibuat slurry propelan A (APh : APk 1:2), propelan B (APh : APk 1:1), propelan C (APh : APk 3:2) dan propelan D (APh : APk 2:1). Metode yang digunakan meliputi pengukuran viskositas dengan viskometer Brookfield RVT spindle 07 pada 0,3 rpm setiap 15 menit. Sementara, di menit ke-35, viskositas pada 0,3; 0,5 dan 0,6 rpm diukur. Berdasarkan data tersebut, grafik ln viskositas vs waktu serta viskositas vs shear rate dibuat untuk menentukan persamaan viscosity build-up dan Power Law. Diketahui, nilai viskositas awal propelan dalam jangkauan 11.493 – 52945 P, dengan viskositas terendah dan pot life (13,12 menit) dimiliki oleh propelan A. Sementara, nilai indeks pseudoplastisitas propelan yang jangkauan 0,655 – 0,991, nilai terendahnya ditunjukkan oleh propelan D dan tertingginya ditunjukkan oleh propelan B, yang mana propelan A diketahui tidak sesuai untuk pencetakan dengan teknik vakum. Pada sisi lain, propelan C relatif baik untuk dikembangkan karena memiliki viskositas (17.506 P) dan laju kenaikan viskositasnya (247 P/menit) yang tidak berbeda jauh dengan propelan A, serta indeks pseudoplastisitas (0,972) sesuai untuk pencetakan dengan vakum. Disimpulkan, hubungan antara rasio APh : APk dengan sifat fluida propelan (viskositas, pot life dan pseudoplastisitas beragam oleh karena faktor packing dari partikel – partikel penyusun propelan.

show abstract

Effect of increasing NCO/OH molar ratio on the physicomechanical and thermal properties of isocyanate terminated polyurethane prepolymer

Cited by 28 publications

References 3 publications

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

Controlled Hydrolytic Degradation of Polyglycolide–Caprolactone-Based Bioabsorbable Copolymer

Pengaruh Komposisi Ap Terhadap Prosesibilitas Slurry Propelan Dengan Kandungan Aluminium Tinggi (Effects of Ammonium Perchlorate Composition on High Content Aluminium Propellant Slurry)

Contact Info

Product

Resources

About