Proprietățile chimice și mecanice ale polimerilor pe bază de amidon
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678.7:547.458.61 (1)
Industries based on macromolecular materials. Rubber industry. Plastics industry (51)
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PASCAL, Larisa. Proprietățile chimice și mecanice ale polimerilor pe bază de amidon. In: Oportunități de implicare a tinerilor în procesul de cercetare, 4 mai 2023, Chişinău. Tipografia "Centrografic”, 2023, Ediția a III-a, pp. 304-307. ISBN 978-9975-88-113-5.
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Oportunități de implicare a tinerilor în procesul de cercetare
Ediția a III-a, 2023
Conferința "Oportunități de implicare a tinerilor în procesul de cercetare"
Chişinău, Moldova, 4 mai 2023

Proprietățile chimice și mecanice ale polimerilor pe bază de amidon

Chemical and mechanical properties of starch-based polymers

CZU: 678.7:547.458.61

Pag. 304-307

Pascal Larisa
 
Universitatea de Stat „Bogdan Petriceicu Hasdeu“, Cahul
 
 
Disponibil în IBN: 10 octombrie 2023


Rezumat

Starch polymers are a type of natural polymers produced from starch macromolecules, which are a complex carbohydrate present in foods such as potatoes, rice, corn, beans, and wheat. Starch consists of two types of monomers: amylose and amylopectin. The chemical and mechanical properties of starch-based polymers depend on the concentrations of these monomers in their structure, since polymers with a high concentration of amylose show a linear structure composed of D-glucose monomers, and those with a high concentration of amylopectin show a branched structure composed of α-D-(1-4)-glucan monomers and α-D-(1-6)-glucan linkages at branch points. The most important chemical properties of starch-based biopolymers are hygroscopicity, pH sensitivity, water resistance, resistance to chemical agents and biodegradability. Starch-based polymers are highly hygroscopic, meaning that they absorb water from the environment. This can affect the mechanical properties and the dimensions of objects made of these polymers. They are reversible, meaning they can be broken down into smaller molecules by hydrolysis, and then they can be recombined into a polymer. They are sensitive to pH and they can degrade in acidic or alkaline environments. And in terms of biodegradability, these biopolymers can be degraded down by microorganisms in natural environments. Also, they being highly degradable, they can be used together with a compostable polymer without affecting their degradation process. The important mechanical properties of starch-based biopolymers are tensile strength and flexibility. Thus, starch-based polymers exhibit a lower tensile strength compared to petroleum-based synthetic polymers, but which can be improved by adding additives. In terms of flexibility, these polymers are highly flexible and they can be molded into various shapes. The chemical and mechanical properties of starch-based polymers can be improved by chemical modifications and addition of additives. In principle, the properties of starch-based polymers can be significantly improved by blending them with synthetic polymers, but this will significantly affect their biodegradability. In general, the starch can be used in the food, pharmaceutical and packaging industries. The biodegradability of packaging plays a very important role, because at the moment, the ecological problem is one of the most serious and the waste made of plastic materials, especially those originating from packaging, disposable tableware, containers etc. produced from synthetic petroleum-based thermoplastic polymers such as polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP) and polystyrene (PS) can be found everywhere and they are accumulated daily in a very large amount. These wastes are carried by the wind and flowing waters, being shredded and spread in all directions, on plains, in mountains, on rivers, lakes etc. In this way these numerous wastes flood our planet and all living things suffer. They suffocate from the chemicals and suffer from intestinal diseases or even die. Therefore, in order to protect the environment, we must put into practice the use of biodegradable packaging, because they decompose in a short time, are fine, resistant and free of toxic substances, and starch-based polymers can come to our aid in their manufacture.

Cuvinte-cheie
biopolymers, biodegradability, Packaging, Starch, environmental protection,

biopolimeri, biodegradabilitate, Ambalaje, Amidon, protecţia mediului