Question 36 (Textile Engineering & Fibre Science)
Match the property from Group I with the characterization technique from Group II.
| Group I | Group II | ||
| P | Spherulite size | 1 | Optical microscopy |
| Q | Degradation temperature | 2 | X-ray diffraction |
| R | Crystalline orientation | 3 | Differential scanning calorimetry |
| S | Melting temperature | 4 | Thermogravimetric analysis |
| (A) | P-2, Q-3, R-1, S-4 |
| (B) | P-2, Q-3, R-4, S-1 |
| (C) | P-1, Q-4, R-2, S-3 |
| (D) | P-2, Q-1, R-3, S-4 |
Answer / Solution
[Show Answer]
Option C
Frequently Asked Questions | FAQs
What is a spherulite structure?
A spherulite structure is a type of microstructure that appears in certain materials, particularly polymers and some minerals. It is characterized by a radial arrangement of fine crystalline fibers or lamellae that emanate from a central nucleation point. The resulting structure is spherical or roughly spherical in shape, hence the name “spherulite.”
Spherulites typically form when a material solidifies from a melt or a solution. As the material cools, small clusters of crystals nucleate at various points throughout the material. These clusters then grow outwards in a radial pattern, producing the characteristic spherulitic structure.
Spherulites can be observed with the aid of microscopy, and their size and morphology can provide insight into the processing and thermal history of the material in which they form. The study of spherulites is important in materials science, as the structure can affect the properties of the material, including its mechanical strength and optical behavior.
What is meant by degradation temperature of polymers?
The degradation temperature of a polymer refers to the temperature at which the polymer begins to break down or decompose due to thermal degradation.
Polymers are long chain molecules made up of repeating units called monomers, and their properties are dependent on the chemical structure and the bonding between these monomers. When a polymer is exposed to high temperatures, the thermal energy can cause the polymer chains to break apart, resulting in a loss of physical and mechanical properties.
The degradation temperature of a polymer can vary depending on its chemical composition and structure. It is typically determined by subjecting the polymer to a series of increasing temperatures and measuring the onset of degradation, which is often indicated by a change in color, weight loss, or the appearance of degradation products.
The degradation temperature is an important parameter for determining the suitability of a polymer for specific applications, as it can affect the lifetime and performance of the material. Polymers with higher degradation temperatures are generally more stable and can withstand higher temperatures without significant degradation, making them suitable for high-temperature applications such as in the automotive or aerospace industry.
Why is crystal orientation is important?
Crystalline orientation is the arrangement of crystalline domains in a material with respect to a particular direction. It is an important parameter that affects the mechanical, optical, electrical, and magnetic properties of the material.
Here are some reasons why crystalline orientation is important:
Mechanical properties: The orientation of crystals can greatly affect the mechanical properties of a material. For example, in metals, the strength and ductility of a material can be significantly improved by aligning the grains in a particular direction. Similarly, in fiber-reinforced composites, the orientation of fibers can influence the strength and stiffness of the material.
Optical properties: The crystalline orientation can affect the optical properties of a material such as birefringence, dichroism, and polarization. For instance, in liquid crystal displays (LCDs), the orientation of liquid crystal molecules in a particular direction determines the polarization and the optical properties of the display.
Electrical and magnetic properties: The orientation of crystals can affect the electrical conductivity and magnetic properties of a material. In some materials, the alignment of magnetic domains can produce a magnetic anisotropy, which is important for various applications in electronics and magnetic data storage.
Manufacturing: Crystalline orientation can also be important in manufacturing processes such as casting, extrusion, and injection molding. In some cases, it may be necessary to control the orientation of crystals to achieve desired properties or to avoid defects.
In summary, crystalline orientation is an important factor that can significantly affect the properties and performance of materials in various applications.
What is melting temperature examples?
Melting temperature, also known as the melting point, is the temperature at which a solid material transitions to a liquid state. The melting temperature can vary depending on the chemical composition and structure of the material. Here are a few examples of melting temperatures:
Water – The melting temperature of pure water is 0°C or 32°F at standard atmospheric pressure.
Iron – The melting temperature of pure iron is 1538°C or 2800°F.
Polyethylene – The melting temperature of low-density polyethylene (LDPE) is around 105°C or 221°F, while high-density polyethylene (HDPE) has a melting temperature of around 130°C or 266°F.
Gold – The melting temperature of gold is 1064°C or 1947°F.
Tungsten – Tungsten has one of the highest melting temperatures of any metal, with a melting temperature of 3422°C or 6192°F.
The melting temperature of a material is an important parameter for various applications, as it can affect the processing, manufacturing, and performance of the material.