What is Plastic

Plastic are macromolecules which consist of repeating monomers, so-called polymers. Polymers are naturally occurring chemical structures. For example, sugar or starch is also a polymer. Polymers consist of long, repeating hydrocarbon chains, much like juxtaposed Lego bricks. These polymers are then – depending on the use of the plastic – different additives, so-called additives added. Additives are, for example, plasticizers, colorants or stabilizers. The plastic can be divided into three categories according to different thermal or mechanical behavior: 

• thermoplastics (they become malleable by heat, this process is reversible)
• thermosets (after heating they remain in their hard form)
• elastomers (pressure and elongation change into short-term changes generated).

One of the first plastics was made of birch: birch pitch, an adhesive that was invented in the Stone Age about 80,000 years ago.

Plastics can therefore be obtained from pure natural substances or be fully synthetic products. 

Fully synthetic plastic is primarily a product of petrochemicals and therefore consists of petroleum (to small parts, it is also made of coal or natural gas). Characteristic of plastic is its longevity, formability, as well as its thermal, mechanical and chemical resistance. Worldwide, 335 million tonnes of plastic were produced in 2016, and in total around 8,300 million tonnes of plastic have been produced since 1950.

Megaplastic 

Large plastic pieces over 1m are called Megaplastik.

Macro plastic 

Bottom macro plastic refers to plastic parts that are large between 5 mm and 1 m. 

Microplastics

There is still disagreement about the exact definition of microplastics, but scientists have agreed on the definition of particle sizes below 5mm in diameter. It is divided into primary and secondary microplastics.
Primary microplastics are actively produced, for example to promote skin abrasion in peeling soaps or it is produced as granules, which is then processed into consumer products. 

Secondary microplastics result from the crushing process of larger plastic particles by means of UV rays, mechanical abrasion and bacterial processes. 

Nanoplastics

Again, one is not quite in agreement with the exact definition. There are studies that count smaller particles under <100nm to nanoplastics, others only below 1000nm (nm = 10 ^ -9 meters). The problem with nanoplastics is its small size and thus ability to diffuse through cells. Currently there are very few research results on the environmental impact and on the health consequences of nanoplastics. A recent study examined shells in nanoplastics and came to the conclusion that nanoplastics lingers for a relatively long time in the body and migrates through it, thereby affecting the organism.
In general, however, it is agreed that the effects of nanoplastics will be more severe than those of microplastics. 

Solid, soluble, gelatinous and liquid polymers

Depending on their state of aggregation, plastic can appear solid, liquid, dissolved or gel-like. Especially in cosmetics, liquid / gel-like plastics (eg polyquaternium in shampoos) and solid microplastics (eg polyethylene balls in peeling soaps) are often hidden. While there is sufficient evidence for the environmental harmfulness of solid microplastics, research in the field of liquid / gelatinous or soluble plastic is still in its infancy. Therefore, cosmetic companies are primarily trying to remove the solid microplastic from the products, but are struggling to do the same with liquid / gel-like plastic. 

Types of plastics and applications

Plastics are subdivided into synthetic or natural (biodegradable or bio-based) plastics, and there are also the blends between the two forms (polyblends). The most commonly used types of plastic belong to the category of synthetic plastics, natural plastics currently account for just 2.08 million tonnes per year (0.6%) (EuropeanBioplastics 2017).

Synthetic plastics

Synthetic plastic is mainly produced from petroleum or natural gas. The largest plastics producers are: China (29%), Europe (19%), NAFTA states (Mexico, USA and Canada) with 18% and rest of Asia (17%).

The following six plastics account for 90% of global plastic production:

• Polyethylene (PE)
• Polypropylene (PP)
• Polyvinyl chloride (PVC)
• Polystyrene (PS)
• Polyurethane (PU / PUR)
• Polyethylene terephthalate (PET)

Thermoplastics 

Up to 2/3 of all plastics are thermoplastics. They are characterized by their thermoformability and their solubility in solvents. Fields of application are almost limitless; from covers, packaging, CDs to bottles and gears. 

Styrene polymers (including PS) 

These include PS, short for polystyrene. PS and other plastics of the group of styrene polymers all use the raw material styrene. Styrene is a liquid, highly inflammable and harmful substance. But styrene polymers are convincing due to their low permeability and can therefore be used as films, as insulating material or in the packaging industry (under the trade name “Styrofoam”).

Polyvinyl chloride (PVC)

PVC is one of the oldest plastics and consists of 57% chlorine salts and 43% petroleum or gas. PVC is fire resistant, lightweight, strong and has low permeability. Depending on the addition, it is issued as hard or soft PVC. PVC is used in the construction industry, as packaging, in medicine and for hoses. PVC was repeatedly criticized because of its health hazard (risk of cancer due to chlorine gas) and its poor recyclability.

Polyolefins (eg PP, PE)

These include: Polyethylene (PE), Polypropylene (PP), as well as Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). 

These plastics are all thermoplastics. In terms of quantity, they represent the largest group of plastics. They have good chemical resistance and insulating properties. They are made of petroleum or natural gas and are produced by polymerisation. Among other things, they are processed into cling films, carrier bags, agricultural films, containers and packaging (as well as drinking straws)  . 

Polyethylene terephthalate (PET)

PET stands for polyethylene terephthalate and consists chemically of alcohol chains connected with acids, the so-called esters, therefore PET belongs to the polyesters. Polyesters are very versatile plastics, they are found as textile fibers, such as Polycotton or Sympatex®, a membrane that makes clothing breathable. In addition, polyester is used in the production of CDs, resins and films. Certain types of polyester also occur naturally and are therefore biodegradable. But they have a low melting temperature and low tensile strength, which reduces their range of use. PET belongs to the aromatic polyesters and possesses excellent material properties, which, however, reduce / destroy biodegradability. Due to its enormous formability, it can be poured for almost any packaging form, so PET is used especially for beverage bottles.

Fluoropolymers 

A thermoplastic of polymers of fluorine atoms, which includes, for example, polytetrafluoroethene (also known as Teflon or when foamed as Gore-Tex). Its versatility and resistance to chemicals and temperatures are characteristic.

Polycarbonate

Chemically, it consists of multiple linkages of alcohols and carbonic acid. The most commonly used in the preparation bisphenol-A. Polycarbonates are characterized by high strength and resistance to water or other solvents. They are transparent and colorless, but have a high sensitivity to UV radiation. Polycarbonates are expensive and are used in automobiles (turn signals) and in electrical and electronic equipment.

Elastomers

Elastomers are not soluble in solvents, but have a high elasticity and return so after deformation back to its original state (rubber). Elastomers are based on natural rubber, among others. However, this is often produced synthetically today. The production of elastomers is more complex and more complex than that of thermoplastics. The most important elastomers include natural rubber and silicone rubber or butadiene rubber. Both elastomers are made from synthetic, mostly petroleum-based raw materials. Fields of application include car tires or seals.

Thermosets

Thermosets can not be remelted and deformed after hardening. This makes their recyclability almost impossible. Applications include boat building or insulation materials.

Phenoplasts (including PU / PUR)

These include epoxy resins, melamine resins, polyurethanes and polyester resins. Epoxy resin is a high quality, expensive plastic and is used for electrical, marine, aerospace and art paint applications. Polyester resins are usually mixed with a reinforcing material and then give a very strong, heat-resistant and durable plastic. This great flexibility is reflected in its versatile field of application. They can then be used in many industrial sectors, such as shipbuilding or construction. Polyurethanes (PU or PUR) are also part of the reaction resins. They are used as soft foams in mattresses and car seats. The rigid foams, on the other hand, serve primarily as insulation material.

Bioplastics

The term bioplastics / bioplastics or agro-plastics is used very broadly. On the one hand, it can mean that the raw material from which the bioplastic was made comes from renewable (biological) products. On the other hand, bioplastics can also mean that the bioplastic is biodegradable. A combination of these two values

Various renewable resources are used to produce bioplastics: maize, sugar cane, wheat, cotton, potato, tapioca, coffee grounds, feathers and much more.

Biodegradable starch products from corn, potatoes, tapioca, wheat or animal origin, such as wool , Silk, gelatin or chitin cellulose from plant fibers, such as from cotton, hemp or linen

polyactide (PLA), also polylactic acid. 

The fermentation of natural carbohydrateslactic acid 

yieldsbut not biodegradable

Bio-basedBio-based polyethylene Bio-PET 30, which consists of 30% renewable raw material.

Polybutylenes Adipate Terephthalate

Renewable bio-based raw materials can in turn be categorized into three categories, depending on how the natural raw material was used to make the final bioplastic

• Biopolymer, for example cellulose, can be obtained and used directly by nature.
• Biologically derived plastics, for example viscose (artificial silk), which were obtained in nature but were then treated chemically.
• On natural resources based plastics such as bio-polyethylene, in which the monomers, although derived from plants, but then processed similar to the synthetic plastics.

According to the Federal Office for the Environment 2017, 3,000 tonnes of biodegradable materials end up in the Swiss market every year, most of them in the form of garbage bags, food boxes, drinking cups and accessories.

Polyblends Polyblends or blends

These are combinations of different polymers. The polymers may be made from renewable (bioplastic) or fossil (synthetic plastic) raw materials. The combination can result in interesting new possibilities. For example, by mixing a degradable, but with less good material properties equipped synthetic polyester with a polymer from renewable resources. The origin of the polyblends can be found in bioplastics or in synthetic plastics, from which the disadvantages can be deduced: among others, the degradability, the ethical conflict and the fossil raw materials. 

Plastic

Additives Plastic additives are the chemical additives that make plastic a functional product. Half of the additives are plasticizers, followed by flame retardants. Many additives have toxic effects when released into the environment. There is also a lack of in-depth knowledge of what happens to the chemical decay products of the additives. Their toxicity, unpredictability and high levels of environmental enrichment make them one of the main causes of the negative environmental impact of plastics.

Important Plastic

Additives Plasticizers Plasticizers

are used to increase flexibility, especially in the production of PVC

Phthalates Flame retardants

Make plastics more resistant to combustion

Polybrominated biphenyls Stabilizers

Protect against UV light, heat, ozone, etc., thus making the plastic last longer.

Bisphenol A

Colorants Are responsible for the color of the plastic, may be organic or non-organic origin

Fillers

Since some plastics are expensive, they try to stretch them with fillers. But there are also those that improve the stability Lime, clay, chalk

Fiber materials

Improve the strength and rigidity Glass fiber, carbon fiber

Plastic is very stable due to its chemical structure and resistant to environmental influences. Most microorganisms are unable to completely decompose the plastics and certain plastics are not degraded by them. This means that plastic is indeed decomposed, but only in smaller particles (micro or nanoparticles), which then deposit. In addition, plastic is not exposed to mineralization (ie its conversion into inorganic substances) because it is very soluble. It is estimated that the removal of a plastic bottle takes up to 450 years. 

There is more and more research indicating that microorganisms and even a caterpillar can break down plastic. But as research is not yet well advanced, it is questionable if these organisms can solve our plastic problem. 

In general, the focus should be on tackling causes instead of combating symptoms. When plastics are burned (eg in waste incineration), some plastics produce toxic products and harmful carbon dioxide. In addition, plastic waste is burned in open fireplaces in many countries and the toxic gases are released directly into the environment.

Also in the production of plastics, there are often toxic products. Microplastic attracts other, toxic substances and there is an increased accumulation of environmental toxins on its surface. Plastic nets, drink holders, plastic leashes and strings pose a deadly threat to thousands of animals. The animals become entangled in it and can be strangled by it.

Sea animals eat plastic in the belief that it is food. This plastic accumulates in the stomach and lets the animals starve to death with their stomachs full, as they can not digest the plastic. The decomposed plastic particles finally reach our humans via food or drinking water.

Additives which give plastics their specific properties are often of a toxic nature (eg plasticizers such as bisphenol-A). It is still completely unclear what happens in the degradation process of plastic with the often toxic plastic additives. All these reasons speak for a sustainable, resource and environmentally friendly handling of plastics such as reuse. 

Especially when you consider that only just 31% of the plastic in Europe is recycled. The rest ends up in landfills (27%) or in the energy recovery category (42%).

According to European Bioplastics and the DIN EN 13432 standard, biodegradable plastic on a composting plant after 3 months at a temperature of 50-65 ° C must reach 90 % degraded. However, since the biological and physical climate of a professional composting plant differs from home compost, it can take up to one year on the house compost (temperatures vary from 0-45 ° C) to decompose the product.

It is also important to mention that if bioplastics are not properly disposed of and end up in nature, there are hardly any conditions necessary to ensure composting within a reasonable period of time.

Among other things, the cultivation and production of the respective bioplastics can also take up a great deal of energy (water, electricity), which can reduce the overall eco-balance. 

The wooden drinking straws, for example, consume more energy than those made of glass.