Determination of Melting Point of Alkylated Phenolic Antioxidants for Paints by Capillary Method (CAT#: STEM-PPA-0046-YJL)

Name: Determination of Melting Point of Alkylated Phenolic Antioxidants for Paints by Capillary Method
SKU: STEM-PPA-0046-YJL
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Introduction

Polymeric materials are gradually degraded by various agents such as ultraviolet (UV) rays, oxygen, hydroperoxides, metal residues, and initiator fragments etc. Because of these agents, they lose their optical properties such as gloss and whiteness in paints. Different types of additives such as antioxidants, UV absorbers and light stabilisers have been used for protecting polymeric materials from such degradation.
Among the various stabilisers, hindered phenols are well known stabilisers which directly trap the peroxy radicals formed during degradation and prevent autooxidation chain reactions. Hindered phenols displace aromatic amine antioxidants which are toxic and can cause discoloration.

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Principle Applications Procedure Materials

Principle

Melting point is a characteristic property of solid crystalline substance. It is the temperature at which the solid phase changes to the liquid phase. This phenomenon occurs when the substance is heated.
The melting point measurement is usually performed in thin glass capillary tubes with an internal diameter of 1 mm and a wall thickness of 0.1 – 0.2 mm. A finely-ground sample is placed in the capillary tube to a filling level of 2 – 3 mm and introduced in a heated stand (liquid bath or metal block) in close proximity to a high accuracy thermometer. The temperature in the heating stand is ramped at a user-programmable fixed rate. The melting process is visually inspected to determine the melting point of the sample.