POM-H和POM-C之间的差异

Key Difference – POM-H vs POM-C

POM stands for polyoxymethylene, a high molecular weightthermoplastic polymer这是一个广泛用于许多工业应用tions. It is also known as polyacetal, acetal, polyformaldehyde. The POMcopolymerof formaldehyde is composed of –CH₂O- repeating units. POM polymers, in general, provides excellent mechanical properties like high tensile strength, low friction, high fatigue resistance and, better stiffness and toughness. Furthermore, POM shows high scratch resistance properties and low moisture absorption. Moreover, it is resistant to many strong bases, many organic solvents, and weak acids, However, due to the chemical structure of the POM, it is not stable in acidic conditions (pH <4) and elevated temperatures as the polymer is degraded under these conditions. Hence, the POM is often copolymerized with cyclic ethers such as ethylene oxide or dioxilane to disturb the chemical structure, thus enhancing the stability of the polymer. POM is available in two variants; copolymers (POM-Cs) and homopolymers (POM-Hs). These two types of POM differ in many ways, but thekey difference between POM-H and POM-C is their melting point. The melting point of POM-C is between 160-175 °C whereas, that of POM-H is between 172-184 °C.Their applications are determined based on the properties of POM-H and POM-C. This article elaborates the difference between POM-H and POM-C.

What is POM-H?

POM-H代表聚乙烯homopolymer。与POM的其他变体相比，均聚物的熔点更高，比共聚物强10-15％。但是，两个变体都具有相同的影响属性。POM-H是由甲醛的阴离子聚合产生的，在该聚合中，结晶的发生良好，从而导致较高的刚度和强度。通常，POM-H比POM-C具有更好的物理和机械性能。POM-H最适合应用诸如耐磨性良好和摩擦系数低的属性。

What is POM-C?

POM-Cstands for polyoxymethylene copolymer. This is produced by cationic polymerization of trioxane. During this process, a small amount of comonomers is added in order to increase the tightness, while lowering the crystallinity. The POM-C however, has low stiffness and strength than POM-H. But its processability is high when compared to POM-H. Because of this reason, POM-C has become the most widely used POM (75% of total POM sales). POM-C is well suited for applications where the property like low coefficient of friction is needed.

What is the difference between POM-H and POM-C?

Full Name

POM-H：Its full name is POM homopolymer.

POM-C:Its full name is POM copolymer.

由。。。生产

POM-C:它是由甲醛的阴离子聚合产生的。

POM-H：它是由三人烷的阳离子聚合产生的

Properties of POM-H and POM-C

硬度和僵硬

POM-H：POM-His hard and stiff

POM-C:POM-Cis not as hard and stiff as POM-H.

Processability

POM-H：Processability is low.

POM-C:Processability is high.

Melting Point

POM-H：熔点为172-184°C。

POM-C:Melting point is 160-175 °C.

Processing temperature

POM-H：Processing temperature of POM-H is 194-244°C.

POM-C:POM-C的加工温度为172-205°C。

Elastic modulus (MPa) (tensile with 0.2% water content)

POM-H：弹性模量为4623。

POM-C:Elastic modulus is 3105.

Glass transition temperature (t_g)

POM-H：Glass transition temperature is -85°C.

POM-C:Glass transition temperature is -60°C.

Tensile strength

POM-H：Tensile strength is 70 MPa.

POM-C:Tensile strength is 61 MPa.

伸长

POM-H：伸长is 25%.

POM-C:伸长is 40-75%.

Usage

POM-H：POM-Hrepresents around 25% of total POM sales.

POM-C:POM-Crepresents around 75% of total POM sales.

申请

POM-H：Bearings, gears, conveyor belt links, seat belts and grinding accessory of hand mixtures are some examples of POM-H.

POM-C:Electric kettles, water jugs, component with snap fits, chemical pumps, bathroom scales, telephone keypads, housings for domestic applications, etc. are some applications of POM-C.

参考：

Cousins, Keith.Plastics and the Market for Small Domestic Appliances: A Report from Rapra’s Industry Analysis Group。Ismithers Rapra Publishing，1998年。

Platt, David K.工程和高性能塑料市场报告：RAPRA市场报告。iSmithers Rapra Publishing, 2003.

Olabisi, Olagoke, and Kolapo Adewale, eds.Handbook of thermoplastics。Vol. 41. CRC press, 2016.

Image Courtesy:

“Polyoxymethylene” By Yikrazuul – Own work (Public Domain) viaCommons Wikimedia