What are the units of glass transition temperature? Which type of polymers undergo glass transition? What are the examples of polymers with high or low Tg? What is the difference between Tg and Tm? Why is it important to identify the Tg of polymers? What are the factors affecting Tg? What are the methods to determine Tg?

What is Glass Transition Temperature (Tg)? Glass transition temperature is the temperature at which an amorphous polymer changes from a hard/glassy state to a soft/leathery state, or vice versa. Tg is directly related to a material’s strength and …

2018年11月5日 · 玻璃轉移溫度 (Glass Transition Temperature, Tg) 或稱玻璃轉移點 (Glass Transition Point) 是高分子塑膠材料一項重要的物理性質，大部分從事塑膠加工人員，並不是很清楚了解此玻璃轉移溫度所代表的物理意義，所以利用此針對玻璃轉移溫度的特徵及現象加以說明。

The glass transition temperature (Tg) is a critical temperature for polymers and plastics, marking the point at which these materials transition from a hard, brittle, and glassy state to a softer, more flexible, and rubbery state. At temperatures below Tg, the polymer chains are frozen in a relatively ordered and rigid structure, akin to a solid.

The Tg of POM depends on its molecular weight; however, for molecular weight higher than 70,000, the Tg remains stable (Chiang and Huang, 1997). The mechanical properties of POM are different for POM homopolymer and copolymer. They depend strongly on average molecular mass and dispersity as well as on the processing method and its conditions.

POM homopolymer sample has 1mm thickness, its crystallinity ratio is close to 63% and a melting temperature of 180°C (DSC). First, glass transition can be observed from -70°C to -20°C, typical value can be assessed by using the maximum of the tan( curve: Tg ~-50°C.

The high degree of crystallinity of POM-H is reflected in the above DSC curve. It is dominated by a distinctive melting effect at 183°C (1st heating, blue, peak temperature) and 181°C (2nd heating, green, also peak temperature) as well as a quite small glass transition step at …

This paper presents the influence of the processing temperatures on the physical–mechanical properties of polyoxymethylenes (POM) used in injection molding of high performance sport products. The test-pieces were obtained by processing POM at the following temperatures: 180°C, 190°C, 200°C, 210°C, 220°C, 230°C and 240°C.

Polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. Good stiffness, toughness and stability. Low humidity absorption. Good dimensional stability. Good electrical insulation properties.

2024年12月17日 · Tg for most synthetic polymers ranges from 170K to 500K (-103°C to 227°C). Polymer thermal properties are strongly dependent on Tg. Polymers show glassy behavior, with high stiffness and brittleness below Tg. At temperatures above Tg, they move into a rubbery state and are more flexible and elastic.