Melting Point of Plastic: Chart for Common Materials

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The melting point of plastic varies depending on the type of polymer, its molecular structure, and its composition. While polyethylene (PE) typically melts between 105°C and 135°C, polypropylene (PP) melts at approximately 160–170°C, and polyethylene terephthalate (PET) melts at around 250–260°C. Other materials, such as ABS and polycarbonate (PC), behave differently because they do not have a distinct crystalline melting point.

Understanding these differences is essential for selecting suitable materials, establishing manufacturing conditions, and maintaining consistent product quality. This guide provides a plastic melting point chart for common thermoplastics, explains the thermal properties of different polymers, and explores how melting temperatures influence plastic processing.

1. What is the melting point of plastic?

The melting point of plastic is the temperature at which the crystalline regions of a polymer transition from a solid state into a molten state. This property, known as the melting temperature (Tm), is particularly relevant to semi-crystalline thermoplastics such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET).

Unlike pure crystalline substances, polymers often melt over a temperature range rather than at one exact temperature. Their melting behavior depends on factors such as molecular structure, crystallinity, molecular weight distribution, and material formulation.

However, not every plastic has a true melting point. Thermoplastics are generally classified into two groups based on their molecular organization: semi-crystalline and amorphous polymers.

Plastic after reaching the melting point

Plastic after reaching the melting point

1.1. Semi-Crystalline Plastics

Semi-crystalline plastics contain both ordered crystalline regions and disordered amorphous regions within their molecular structure.

When heated, these materials undergo a glass transition in their amorphous regions and, at higher temperatures, melting of their crystalline regions. The melting temperature is therefore an important characteristic when evaluating their processing behavior.

Common semi-crystalline thermoplastics include:

Polyethylene (PE), including LDPE and HDPE
Polypropylene (PP)
Polyethylene terephthalate (PET)
Polyamide (PA6 and PA66)
Polybutylene terephthalate (PBT)
Polyoxymethylene (POM)

These materials exhibit measurable melting transitions, although their exact melting ranges vary depending on the polymer grade and formulation.

1.2. Amorphous Plastics

Amorphous plastics have polymer chains arranged without long-range crystalline order. Consequently, they do not exhibit a distinct crystalline melting point. Instead, they undergo a glass transition, characterized by the glass transition temperature (Tg). As the material is heated through this region, molecular mobility increases, and the polymer gradually changes from a rigid, glassy state to a softer, more flexible state.

Common amorphous thermoplastics include acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), and most commercial PVC formulations. These materials can still be softened and processed at elevated temperatures. However, the temperatures used during manufacturing should not be described as their true melting points.

This distinction is particularly important when comparing plastic melting temperatures or selecting materials for injection molding and extrusion.

For further technical information, see the study Waste Electrical and Electronic Equipment: A Review on the Identification Methods for Polymeric Materials, which presents thermal transition data for several common polymers.

2. What Is the Melting Point of Different Plastic Materials?

The following plastic melting point chart compares the typical melting temperatures of widely used semi-crystalline thermoplastics and the glass transition temperatures of common amorphous plastics.

These values are general material references rather than fixed processing specifications. Actual temperatures may vary depending on polymer grade, additives, molecular structure, and testing conditions.

Plastic material	Polymer structure	Melting point (Tm)	Glass transition temperature (Tg)
Low-Density Polyethylene (LDPE)	Semi-crystalline	105–115°C	Approximately −110°C
High-Density Polyethylene (HDPE)	Semi-crystalline	125–135°C	Approximately −110°C
Polypropylene (PP)	Semi-crystalline	160–170°C	Approximately −20 to −10°C
Polyethylene Terephthalate (PET)	Semi-crystalline	250–260°C	70–80°C
Polyamide 6 (PA6)	Semi-crystalline	215–225°C	Approximately 50°C
Polyamide 66 (PA66)	Semi-crystalline	255–265°C	Approximately 50–70°C
Polybutylene Terephthalate (PBT)	Semi-crystalline	220–230°C	45–60°C
Polyoxymethylene (POM)	Semi-crystalline	165–175°C	Approximately −60°C
Polyvinyl Chloride (PVC)	Predominantly amorphous	No distinct Tm	Approximately 80°C for rigid PVC
Polystyrene (PS)	Amorphous	No distinct Tm	90–105°C
Acrylonitrile Butadiene Styrene (ABS)	Amorphous	No distinct Tm	Typically around 100–110°C, depending on formulation
Polycarbonate (PC)	Amorphous	No distinct Tm	Approximately 145–150°C

Note: The values are approximate reference ranges for common unmodified grades. Copolymers, filled compounds, reinforced grades, and other formulations may exhibit different thermal properties. ABS can show multiple thermal transitions because of its multiphase structure.

Sources: Polymer thermal properties – MDPI and Polymer Technical Properties – Erk-Han.

2.1. What Is the Melting Point of Polyethylene (PE)?

Polyethylene is one of the most widely used thermoplastics in packaging, films, pipes, containers, and various industrial products. Its melting temperature depends primarily on polymer density, branching, and crystalline structure. The two most common types are low-density polyethylene (LDPE) and high-density polyethylene (HDPE).

Low-Density Polyethylene (LDPE) typically melts at approximately 105–115°C (221–239°F). Its highly branched molecular structure limits the formation of tightly packed crystalline regions, resulting in a relatively low melting temperature.

LDPE is widely used in flexible films, shopping bags, packaging, and extrusion coating applications. Its flexibility and processing characteristics make it particularly suitable for products that require good elongation and ease of forming.

High-Density Polyethylene (HDPE) generally melts at approximately 125–135°C (257–275°F). Compared with LDPE, HDPE has a more linear molecular structure and higher crystallinity, contributing to its higher melting temperature and greater stiffness.

Common HDPE applications include bottles, containers, pipes, crates, and industrial packaging.

Although both materials belong to the polyethylene family, their different melting characteristics affect processing conditions, dimensional stability, and material selection.

2.2. What Is the Melting Point of Polypropylene (PP)?

Polypropylene (PP) typically has a melting point of approximately 160–170°C (320–338°F) for common isotactic homopolymer grades, although copolymer formulations may exhibit different melting behavior. PP is a semi-crystalline thermoplastic widely used in injection molding, packaging, automotive components, household goods, and industrial applications.

Compared with polyethylene, polypropylene generally has a higher melting temperature. This contributes to its suitability for applications requiring greater resistance to elevated temperatures, although its actual service performance must also be evaluated using other thermal and mechanical properties.

The melting temperature of PP depends on several factors, including the degree of crystallinity, molecular configuration, and comonomer content. For instance, polypropylene random copolymers may exhibit lower melting temperatures than conventional PP homopolymers because the presence of comonomer units affects crystalline organization.

In manufacturing, understanding the melting characteristics of PP helps processors establish suitable melt temperatures, evaluate material flow, and control product quality. However, the actual barrel and melt temperatures used during injection molding or extrusion are typically higher than the polymer's crystalline melting point, depending on the selected grade and processing requirements.

2.3. What Is the Melting Point of Polyethylene Terephthalate (PET)?

Polyethylene terephthalate (PET) has a typical crystalline melting temperature of approximately 250–260°C (482–500°F). This makes it one of the higher-melting common thermoplastics used in packaging and textile applications.

PET is a polyester polymer widely used in beverage bottles, food packaging, textile fibers, and various industrial products.

Its melting behavior is associated with the crystalline regions of its polymer structure. However, PET products may have different levels of crystallinity depending on their manufacturing and cooling conditions.

For example, rapidly cooled PET can remain largely amorphous, while controlled crystallization produces structures with different thermal and dimensional characteristics.

In addition to melting temperature, moisture control is particularly important during PET processing. PET is susceptible to hydrolytic degradation when processed at high temperatures in the presence of excessive moisture, which can reduce molecular weight and negatively affect mechanical properties.

Consequently, proper drying and suitable processing conditions are essential for maintaining material quality during PET manufacturing.

2.4. What Is the Melting Point of PVC Plastic?

Polyvinyl chloride (PVC) does not have a distinct crystalline melting point under typical commercial conditions. Most PVC formulations are predominantly amorphous, meaning their thermal behavior is better described using glass transition and processing temperatures.

Rigid PVC generally has a glass transition temperature of approximately 80°C (176°F). As the material is heated, its molecular mobility increases, and it gradually softens.

However, the thermal behavior of PVC depends significantly on its formulation.

Rigid PVC, commonly used in pipes, fittings, and construction profiles, contains little or no plasticizer and typically maintains greater rigidity at moderate temperatures.
Flexible PVC contains plasticizers that lower its glass transition temperature and increase flexibility, making it suitable for applications such as cable insulation, flexible tubing, and flooring.

Unlike semi-crystalline polymers, PVC processing requires careful temperature control because the material can undergo thermal degradation when exposed to excessive heat or prolonged residence times. Therefore, a temperature range listed for PVC extrusion or injection molding should be understood as a processing reference rather than a true melting point.

2.5. What Is the Melting Point of Polystyrene (PS)?

Polystyrene (PS) is an amorphous thermoplastic that does not exhibit a distinct crystalline melting point. Instead, general-purpose polystyrene typically has a glass transition temperature of approximately 90–105°C (194–221°F). Above this temperature range, the material gradually softens as molecular mobility increases.

PS is commonly used in disposable containers, packaging, appliance components, and other molded products. Its relatively straightforward processing characteristics make it suitable for various manufacturing methods.

However, the temperature at which polystyrene begins to soften should not be confused with the melt temperature required for industrial processing.

During injection molding or extrusion, PS is heated sufficiently to achieve the flow properties necessary for shaping. These processing temperatures are significantly higher than its glass transition temperature and must be controlled to avoid material degradation. Understanding this distinction is essential when evaluating the thermal behavior and manufacturing requirements of polystyrene products.

3. How Does Melting Point Differ from Other Plastic Temperatures?

Although the terms melting point, processing temperature, and heat resistance are sometimes used interchangeably, they refer to different material properties. Understanding these differences is essential for interpreting technical data sheets and selecting appropriate manufacturing conditions.

3.1. Melting Point vs. Glass Transition Temperature

The melting temperature (Tm) describes the transition of crystalline polymer regions into a molten state.

In contrast, the glass transition temperature (Tg) describes the temperature region where amorphous polymer segments gain greater molecular mobility, causing a change from glassy to more rubber-like behavior.

Semi-crystalline plastics can exhibit both transitions, while fully amorphous plastics do not have a distinct crystalline melting point.

Property	Melting Temperature (Tm)	Glass Transition Temperature (Tg)
Main significance	Melting of crystalline regions	Increased molecular mobility in amorphous regions
Relevant materials	Semi-crystalline polymers	Both amorphous and semi-crystalline polymers
Thermal behavior	Crystalline structure melts	Material transitions from glassy to more flexible behavior
Examples	PP, PE, PET, PA6	ABS, PS, PC, PVC

This distinction explains why assigning a single melting point to every thermoplastic can lead to inaccurate material comparisons.

3.2. Melting Point vs. Processing Temperature

The melting point of plastic is a material property, while processing temperature is a manufacturing parameter.

For semi-crystalline polymers, the recommended processing temperature is generally above the melting point to provide adequate melt flow for molding or extrusion.
For amorphous polymers, processing temperatures are selected based on viscosity, flow behavior, thermal stability, and equipment requirements rather than a crystalline melting point.

For example, polypropylene may melt around 160–170°C, while its recommended melt processing temperature can be substantially higher, depending on the grade and manufacturing process.

Similarly, ABS has no true crystalline melting point, although it can be processed at elevated temperatures once its viscosity becomes suitable for molding.

Manufacturers should therefore refer to grade-specific technical data sheets rather than using melting point values as direct machine temperature settings.

3.3. Melting Point vs. Maximum Service Temperature

Maximum service temperature refers to the temperature at which a plastic product can operate under specified conditions while maintaining acceptable performance. Unlike melting temperature, service temperature depends on several factors, including mechanical loading, exposure duration, dimensional stability, and environmental conditions.

A polymer may soften, creep, or deform at temperatures considerably below its melting point, especially when subjected to sustained mechanical stress. For this reason, melting temperature alone cannot determine whether a plastic material is suitable for continuous high-temperature applications.

Other thermal indicators, such as heat deflection temperature (HDT), Vicat softening temperature, and continuous-use temperature ratings, may be more relevant for evaluating product performance.

4. What Factors Affect the Melting Point of Plastic?

The melting behavior of polymers is influenced by their molecular structure, crystalline organization, and formulation. Understanding these factors helps manufacturers interpret differences between plastic grades and optimize material selection.

4.1. Polymer Structure and Crystallinity

Molecular structure is one of the primary factors influencing polymer melting behavior. Polymers with more regular molecular arrangements can form crystalline regions, while irregular molecular structures may limit crystallization.

For example, HDPE generally has a higher melting temperature than LDPE because its more linear molecular structure allows greater crystalline organization. Similarly, different polypropylene grades may exhibit different melting temperatures due to variations in molecular configuration and comonomer content.

The degree and structure of crystallinity also affect melting behavior, although changes in crystallinity often influence the shape and intensity of the melting transition more directly than the intrinsic melting temperature itself.

4.2. Molecular Weight and Polymer Composition

Molecular weight distribution and polymer composition can influence thermal transitions and processing behavior. Changes in molecular structure, including branching and copolymer composition, may alter the formation and stability of crystalline regions.

For instance, incorporating certain comonomers into polypropylene can disrupt crystalline packing and lower the material's melting temperature.

However, molecular weight should not be treated as a simple predictor of melting temperature. Its influence depends on the polymer system and the relationship between chain structure, crystallization, and thermal behavior.

4.3. Additives, Fillers, and Reinforcements

Plastic materials often contain additives, fillers, or reinforcing agents to modify their physical, mechanical, or processing characteristics. These components may affect crystallization behavior, thermal conductivity, dimensional stability, and the overall thermal response of the finished compound.

For example, certain additives can act as nucleating agents and influence the crystallization rate of semi-crystalline polymers. Mineral fillers and glass fibers may improve stiffness or dimensional stability under specific conditions.

However, adding fillers or reinforcements does not necessarily increase the intrinsic melting temperature of the base polymer.

Therefore, when evaluating filled or reinforced compounds, manufacturers should distinguish between changes in the polymer's melting behavior and improvements in the compound's overall thermal performance.

5. Why Is the Melting Point of Plastic Important in Manufacturing?

Understanding plastic melting temperatures helps manufacturers establish suitable processing conditions, evaluate material compatibility, and maintain consistent product quality.

5.1. Selecting Suitable Plastic Materials

Different polymers exhibit different thermal characteristics, which influence their suitability for specific applications. For example, LDPE is commonly selected for flexible film applications, while PP is used in a wide range of packaging and molded products requiring greater stiffness and moderate heat resistance.

Engineering plastics such as PA6, PA66, and PC may be considered for applications with more demanding mechanical or thermal requirements.

However, material selection should not depend solely on melting point. Manufacturers must also evaluate impact strength, stiffness, chemical resistance, dimensional stability, and operating conditions.

5.2. Establishing Appropriate Processing Conditions

Melting behavior provides an important reference when setting up plastic manufacturing processes. During injection molding and extrusion, the polymer must reach a suitable flow state while remaining within a temperature range that avoids excessive degradation.

If the melt temperature is too low, the material may exhibit insufficient flow, incomplete mold filling, or unstable extrusion.

Conversely, excessive processing temperatures can increase the risk of thermal degradation, discoloration, gas formation, and deterioration of mechanical properties.

The optimal temperature profile depends on the selected polymer grade, machine configuration, residence time, and processing method.

5.3. Maintaining Product Quality and Production Stability

Consistent temperature control is essential for achieving stable production and finished-product quality. Variations in melt temperature can affect viscosity, material flow, crystallization behavior, and dimensional consistency.

In injection molding, inappropriate temperature settings may contribute to defects such as short shots, sink marks, warpage, or surface imperfections.
In extrusion, unstable temperatures can influence melt pressure, output consistency, and the quality of the extruded product.

By understanding material thermal characteristics and following grade-specific processing recommendations, manufacturers can improve process control and reduce the risk of quality variations.

6. Frequently Asked Questions About Plastic Melting Points

6.1. At What Temperature Does Plastic Melt?

Plastic does not have one universal melting temperature. Common semi-crystalline polymers have different melting ranges: LDPE typically melts around 105–115°C, HDPE around 125–135°C, PP around 160–170°C, and PET around 250–260°C. Amorphous plastics such as ABS, PC, and PS soften over a temperature range rather than exhibiting a distinct crystalline melting point.

6.2. Which Common Plastic Has the Lowest Melting Point?

Among widely used commodity thermoplastics, LDPE has a relatively low melting temperature of approximately 105–115°C. However, some specialty polymers and polymer formulations can exhibit lower melting temperatures. The comparison should therefore be limited to a defined group of materials rather than applied to all plastics.

6.3. Which Plastic Has the Highest Melting Point?

Among the common polymers discussed in this guide, PA66 and PET have relatively high melting temperatures of approximately 255–265°C and 250–260°C, respectively. Other high-performance polymers, such as PTFE and PEEK, have significantly higher melting temperatures. However, melting point alone does not determine maximum operating temperature.

6.4. Do All Plastics Have a Melting Point?

No. Semi-crystalline thermoplastics such as PE, PP, PET, and PA exhibit measurable crystalline melting temperatures. Amorphous thermoplastics, including ABS, PC, PS, and most PVC formulations, do not have a distinct crystalline melting point. Instead, they soften progressively as temperature increases beyond their glass transition region.

6.5. Is Melting Point the Same as Heat Resistance?

No. Melting point describes the thermal transition of crystalline polymer regions, while heat resistance refers to a material's ability to maintain acceptable properties under elevated-temperature conditions. A plastic can deform or lose mechanical strength well below its melting point, particularly under load or prolonged heat exposure.

6.6. Can Additives Increase the Melting Point of Plastic?

Additives can influence crystallization behavior, thermal stability, and the performance of plastic compounds. However, conventional fillers and reinforcements do not necessarily increase the intrinsic melting point of the base polymer. Improving heat resistance often involves selecting suitable polymers, modifying compound formulations, or enhancing mechanical stability at elevated temperatures.

7. Conclusion

The melting point of plastic is an important thermal property that helps manufacturers understand polymer behavior, select suitable materials, and establish appropriate processing conditions. However, different plastics respond to heat in different ways, making it essential to distinguish between crystalline melting temperature, glass transition temperature, processing temperature, and service temperature.

For semi-crystalline materials such as PE, PP, PET, and PA, melting temperature provides a useful reference for evaluating material characteristics. For amorphous polymers such as ABS, PC, PS, and PVC, glass transition and processing behavior are more relevant indicators.

8. About EUROPLAS

EUROPLAS is the plastic materials brand of European Plastic Joint Stock Company (EuP), one of the world’s leading filler masterbatch manufacturers. With 19 years of experience, EuP operates a network of seven manufacturing plants in Vietnam and Egypt, with a total production capacity of approximately 0.9 million tons per year and exports to more than 95 countries worldwide. In addition to filler masterbatch as its core product line, EuP offers a diversified portfolio of material solutions, including bioplastic compound, color masterbatch, plastic additives, biofillers, and engineering plastic compound. for a wide range of plastic manufacturing applications.

Contact us today to discover our wide range of products and find the ideal plastic solution that is customized to meet your specific requirements. Explore more valuable information right here!

9. About the Author

EuP Technical Content Team

This article was prepared by the EuP Technical Content Team in collaboration with EuP's specialist team, based on knowledge and experience in plastic materials, masterbatch, additives, and engineering plastic compounds. EuP aims to provide clear and practical technical information to help manufacturers better understand material properties, potential applications, and key considerations when selecting plastic materials for production.

The information provided in this article is for reference purposes. Formulation, loading levels, and material performance should be evaluated according to the polymer type, processing technology, and actual end-use conditions.