The discovery, use in plastic materials and reactions in polymer recipes

Speaking of recycled plastic material additives, today we tell, not only the story of peroxide, a well-known polypropylene fluidifier with roots which date back to two centuries ago, but also how to use it in modifying recipes and what negative and positive aspects it can have, on the other physical-mechanical characteristics of plastic.

Hydrogen peroxide, commonly known as hydrogen peroxide, it is a chemical element composed of two hydrogen atoms and two oxygen atoms (H2O2). Its discovery and development has been a gradual process throughout history.

In 1818, the French chemist Louis Jacques Thénard was the first to isolate hydrogen peroxide in the form of white crystals. He prepared the compound by reacting concentrated sulfuric acid with barite peroxide.

In 1857, the German chemist Richard Wolffenstein synthesized hydrogen peroxide in liquid form for the first time. Later, in 1894, the French chemical engineer Charles-Adolphe Wurtz developed a method for producing commercial hydrogen peroxide.

During the 20th century, peroxide became an increasingly used chemical compound in various industries. It has been used as a disinfectant, bleaching agent, oxidizer, rocket fuel and in other applications.

During the 70s of the last century, peroxide  has attracted attention as a greener alternative to chlorine compounds in the pulp and paper industry. Its oxidizing and bleaching properties have been exploited to reduce the environmental impact of chlorine bleaching.

Over the last few decades, hydrogen peroxide has continued to be used in many industrial and commercial sectors, becoming a common ingredient in personal care products, the home, disinfectant solutions and many other applications.

Applications in the field of plastic materials

In the 60s and 70s of the last century, studies were carried out on the modification of polymers through the use of organic peroxides. Hydrogen peroxide has been used as a trigger agent for controlled polymerization reactions, leading to the development of new polypropylene blends with improved properties.

During the 1980s, the use of hydrogen peroxide in blending polypropylene played a significant role in the optimization of the properties of polymer blends. The main objective was to improve the impact resistance of polypropylene while reducing stiffness and brittleness.

During the 1990s, methods were developed for in-situ blending of polypropylene with hydrogen peroxide, in order to improve the compatibility of polymer blends. These studies have shown that the use of hydrogen peroxide as a mixing agent can increase the homogeneity of the mixtures and improve the mechanical properties.

During the early 2000s, the use of hydrogen peroxide in polypropylene blends focused on changing the thermal properties and heat resistance. Controlled cross-linking processes through the use of hydrogen peroxide have been developed to improve the thermal stability and resistance to high temperatures of the blends.

Currently, the use of hydrogen peroxide in polypropylene blends is widely studied for different objectives, such as the modification of mechanical properties , thermal and resistance to external agents.

Research continues to evaluate the potential of using hydrogen peroxide to improve the properties of polymer blends and to develop new materials with superior performance.

How the polypropylene fluidization process takes place using peroxide

Hydrogen peroxide (H2O2) is used in the liquidification of polypropylene to improve its rheological properties and facilitate the process of processing. Polypropylene fluidization consists of reducing the viscosity of the plastic material to allow for better flow during injection or ejection from a mold.

The peroxide creates a controlled polymer degradation reaction. The reaction of the peroxide with the polypropylene leads to the breaking of the polymer chains, thus decreasing the viscosity of the material and improving its workability.

How peroxide affects the mechanical strength of polypropylene

The effect of peroxide on the mechanical strength of polypropylene depends on the treatment conditions, the percentage of peroxide used in the recipe, and the exposure time.

In general, the use of peroxide in the fluidization of polypropylene can lead to a decrease in the mechanical strength of the material. However, this effect depends on several factors:

Peroxide use percentages: the use of higher concentrations of the additive can cause greater degradation of the polypropylene, which in turn, as we have said, can reduce the mechanical strength of the material. It is important to balance the peroxide percentage to achieve adequate liquefaction without excessively compromising mechanical strength.

Exposure time: The peroxide exposure time affects the amount of degradation that occurs in the polypropylene. A longer treatment time can lead to greater degradation and, consequently, a reduction in mechanical strength.

Type of polypropylene: Different types of polypropylene can react differently to peroxide treatment. The composition and molecular structure of polypropylene can influence its susceptibility to degradation and, therefore, its mechanical strength.

It is important to carefully evaluate the conditions of use of the peroxide, to obtain a balance between optimal fluidization and maintenance of the desired mechanical properties of the polypropylene.

The choice of peroxide percentages and treatment parameters should be based on the specific needs of the final application and the required properties of the polypropylene.

Benefits of using peroxide in recycled polypropylene blends

The use of peroxide in recycled polypropylene blends can help improve the properties of the material and facilitate its use in various applications. Some of the benefits and applications of using peroxide in recycled polypropylene blends can be:

Improved compatibility: Adding peroxide to recycled polypropylene blends can improve compatibility between material components. This can promote better mixing and greater homogeneity, improving the mechanical and thermal properties of the recycled polymer.

Removal of impurities: Hydrogen peroxide can help remove impurities and contaminants found in recycled polypropylene. The oxidizing action of the peroxide can help remove unwanted substances and improve the quality of the recycled material.

Modification of properties: The use of peroxide can allow the properties of recycled polypropylene to be modified to make it suitable for specific applications. For example, peroxide treatment can increase the impact strength, heat resistance, or chemical resistance of recycled polypropylene.

Odor reduction: Peroxide can help reduce unwanted odors associated with recycled polypropylene. The oxidizing action of hydrogen peroxide can help eliminate or reduce odor-causing molecules, thereby improving the quality of the recycled material.

Automatic translation. We apologize for any inaccuracies. Original article in Italian.