Density can be converted to specific gravity by dividing the Density value (in g/cm³) by 0.9975. Different types of plastics have different densities. Continue reading, you’ll learn more about different plastic densities.

What is the Density of Plastic Materials?

The ratio of mass to volume is referred to as density. It is calculated by dividing the material’s mass by volume, and it is typically expressed in g/cm3. Most of the time, temperature changes affect how dense plastics become. Additionally, it could alter as a result of solvent absorption, plasticizer loss, and crystallinity changes.

Therefore to figure the accurate density of plastic material, certain things need to be taken care of, such as:

• Identifying the material
• Observe and follow the physical changes in the specimen
• Specify the consistency among different Samling specimens
• Specify the average density of a large item
• Calculate the strength weight and cost-weight ratios

What Are the Basics of Density?

Density measures the mass per unit volume. It is calculated by dividing the mass of the material by the volume and is normally expressed in g/cm³.

The density of a plastic sample may change due to changes in crystallinity, loss of plasticizers, absorption of solvent, etc. It is important to note that density varies with temperature.

Therefore, to determine the exact density of plastic, it is important to:

• Identify the Material
• Follow the physical changes in the sample
• Indicate the uniformity among different sampling specimens
• Indicate the average density of a large item, and
• Calculate the strength weight and cost-weight ratios

Density can be converted to specific gravity by dividing the Density value (in g/cm³) by 0.9975.

What is the Bulk Density of Plastic Materials?

The weight of a substance based on a specific volume is known as the bulk plastic density. Bulk density is expressed in three different ways:

• Pounds per cubic foot (lb/cu ft)
• Grams per cubic centimeter (g/cc)
• Kilograms per liter (kg/l)

The bulk densities of each plastic material vary. The weight of plastic material processed through their machinery is therefore used by manufacturers to gauge productivity.

How to Calculate the Density of Plastic?

The same formula can be used to determine the density of any material or object: divide the object’s total mass by its total volume. Although you might need to use different methods to find the volume or the mass of different substances, you would calculate the density, in the same way, using this formula:

The most usual test methods to determine plastics Density are (of course there exist several other methods as well, but they are not discussed here):

Astm D1505

The density-gradient method is used by ASTM D1505 to determine a material’s density. Standard floats, or known-density glass beads, are used to place material in a liquid column of variable density. The material’s density is then determined using its position in relation to the floats in the column and the densities of the glass beads.

Astm D792 – 98

In accordance with ASTM D792 – 98, the specific gravity (relative density) and density of solid plastics in shapes like sheets, rods, tubes, or molded items are determined. There are chiefly two test methods involved:

• Test Method A – For testing solid plastics in water, and
• Test Method B – For testing solid plastics in liquids other than water

Iso 1183-2

In order to determine the density of non-cellular plastics that have been molded or extruded in void-free form, the method specifies a gradient column method. Columns with a mixture of two liquids that are density gradient columns have an even increase in density from top to bottom.

What is the Density of a Variety of Plastics, PVC & Its Usage?

Polymer Generic Name	Abbreviations	Density (gm/cc)	Application or Uses
Acrylic Butadiene Styrene	ABS or Acrylic	1.05 – 1.10	Sheet, pipe, dolls, four-wheeler body parts, etc.
Cellulose Acetate	CA	1.26	cigarettes filters, playing cards, synthetic fiber, etc.
Ethylene Vinyl Acetate	EVA	0.95	Electronic applications
Nylon (Polyamide)	PA	1.02 – 1.08	Clothing, Fiber, etc.
Polybutylene	PB	0.92	Electric domestic heaters, swimming pool water filter housing, pneumatic tanks, etc
Polycarbonate	PC	1.20	equipment used in engineerings, such as safety goggles and helmets.
Polyster PBT	Polyster PBT	1.24 – 1.34	Electrical Insulators
Polyethylene terephthalate	PET	1.40	sheets, food packaging, bottles, etc.
Polyetherimide	PI	1.27	displays, high-temperature fuel cells, and various military functions.
Low-Density Polyethylene	LDPE	0.92	Containers, dolls, lab tubes, plastic bags, trays, etc.
High-Density Polyethylene	HDPE	0.94 – 0.97	Plastic materials, such as geomembrane, plastic lumber, and corrosion-resistant pipes, are common.
Polystyrene	PS	1.07	Plumbing, roofing, packaging, etc.
Polypropylene	PP	0.90	packaging, office supplies, tools for the lab, linens, reusable containers, etc.
Polysulfone	PSU	1.25	Polymeric coating
Polyurethane	PU	1.20	Roof coating, construction coating, etc.
Polyvinyl Chloride-Rigid	PVC-Rigid	1.40	items like dolls, sheets, pipes, and tubes
Polyvinyl Chloride-Pipe	PVC-Pipe	1.44	Pipe
Polyvinyl Chloride-Flexible	PVC-Flexible	1.29	stationery, packaging, etc.
Styrene Acrylonitrile	SAN	1.08	Jugs, jars, food packaging, storage containers, etc. that are thermally insulated.
Thermoplastic Elastomer (Urethane)	TPE	0.97	Construction, electrical, automotive, medical, etc.
Rubber (Santoprene)		1.08	toys, a hairband, a gasket, etc.
Chlorinated Polyvinylchloride	CPVC	1.44	High strength Pipe
Ethylene Propylene Diene Rubber	EPDM	1.08	Rubber, gasket, etc.
Polybutylene Terephalicate	PBT	0.92 – 0.96	Insulator in electrical application
Polymethyl methacrylate	PMMA	1.18	Clear glass, a door, etc.
Polyterafluroethylene	PTFE	2.20	Cookware, pipes, containers, airplane wings, etc.
Fiber Reinforced Plastic	FRP	1.74 – 1.94	sheets, gratings, riser pipes, header pipes, etc.
Glass Reinforced Plastic	GRP	1.90 – 1.95	sheets, gratings, riser pipes, header pipes, etc.

Why is the Bulk Density of Plastic Materials Important?

Storage issues arise from bulk plastic density. For instance, plastic material is frequently packed or stored in a specific size container. Although the bulk densities of various resin pellets vary, similar-sized containers of various materials will have wildly different material weights.

The sizing of drying equipment is also influenced by bulk density. The required weight of the material must be dried at the proper temperature for the prescribed residence time in order for the drying operations to continue without interruption. In order to guarantee the correct output of dried material for processing at the appropriate time, the hopper’s size is crucial.

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