Tezislər / Theses

THE 3
rd
 INTERNATIONAL SCIENTIFIC CONFERENCES OF STUDENTS AND YOUNG RESEARCHERS 
dedicated to the 99
th
anniversary of the National Leader of Azerbaijan Heydar Aliyev
388
PREPARATION AND ENHANCEMENT OF STARCH BASED 
BIODEGRADABLE PLASTIC WITH THE ADDITIVE (GLYCEROL) 
AND TIO
2
 FILLER. 
Gunel Rahimli, Vusala Valiyeva, Shahin Huseynli 
Baku Higher Oil School 
Baku, Azerbaijan 
[e-mail]
Supervisor: Prof. Amir Reza Vakhshouri 
Keywords: 
Starch, mechanical properties, biodegradable plastics
 
 
The invention of plastic brought numerous changes to the industrial 
world and within short period it turned of main material of manufacturing that 
replaced such as woods, textile, bags. While the plastic century brought the 
convenience and cost effectiveness, it trigged problematic environmental 
cases. However, only a small amount of plastics can be recycled and huge 
percentages are made of non-renewable materials and plastic packages was 
to be designed single-use. The materials are going to decompose within 
centuries that was the main reason of forming enormous waste. In order to 
overcome long-winded plastic decomposition, the biodegradable plastics can 
be produced to adding several additives to synthetic polymers and its 
features can be enhanced that may use in daily life (Lu D. R. 2009). Several 
investigations have been conducted on numerous materials and starch 
utilized in that experiment is considered as one of the most cost-effective, 
high-quality and abundant one.
The decomposition of plastic glasses 

---

THE 3
rd
 INTERNATIONAL SCIENTIFIC CONFERENCES OF STUDENTS AND YOUNG RESEARCHERS 
dedicated to the 99
th
anniversary of the National Leader of Azerbaijan Heydar Aliyev
389
Native starch is not considered as thermoplastic material as intermolecular 
forces and hydrogen bonds in starch prohibit being pliable and/or moldable 
at high specific temperature and hardening after cooling. Because of this 
reason, plasticizers which are liquid having mostly high boiling point and 
molecular weight between 300-600 are utilized to eliminate its undesirable 
properties and make it more deformable. A plasticizer decreases tensile 
strength, glass transition temperature and enhances flexibility of polymer 
chain, toughness, fracture resistance and processability in the starch (B. 
Khan, 2016). Here, glycerol with the presence of water which is the rich with 
hydroxyl group is used as plasticizer due to its abundancy, great boiling point 
and minimum cost.
The reason why water is not used alone in plasticization 
process is that it reduces the viscosity, leading to more volatile material. As 
a consequence, steam generation in material cause to foaming, bubbles, 
which are not favored. Since glycerol has low molecular weight and size is 
small, it dominates intermolecular spaces between polymer chains and 
interactions among them are eliminated. Being less forces leads to reduction 
in energy content needed for movement of molecule and in generation of 
hydrogen bond. The result is that addition of plasticizer boost up free volume 
of polymer. TPS illustrates viscoelastic and physico-chemical properties similar 
to synthetic polymers. Molecular weight, amylose /amylopectin proportion, 
processing condition, plasticizer concentration and chemical origin all influence 
the final features of TPS. The elongation at breakage is reduced when quantity 
of glycerol was increased, however generally increase in amount of 
plasticizer rises the elongation at rupture. The starch plasticized with glycerol 
also has certain faults, such as low gas permeation, insufficient water barrier 
property, hygroscopicity nature. The main problem is that even though 
thermoplastic starch is form of amorphous, crystallization of material breaks 
forming intense hydrogen bonds in progress of time which results brittleness 
and damage of mechanical strength. Furthermore, glass transition temperature 
(T
g
) of starch is not precise, but approximately between -75 °C and 10°C and 
it is intuitively obvious that this interval is not suitable for production as TPS 
swells irreversibly above its T
g 
(Robbert A). TPS is also hydrophilic, so it is 
vulnerable to moisture, and this characteristic cause the damage to dimensional 
stability and mechanical properties of material. As it was mentioned before, 
the obtained TPS is still sensible to water because of its strong hydrophilic 
nature. Cross-linking method can be followed for reducing hydrophilic 
behavior of starch, as well as increasing thermal stability and decreasing 
swelling power (SP) and solubility which in turn enhances its utilization in 
food packaging applications. The most common cross-linking agents for 
starch are 
glutaraldehyde, epichlorohydrin, citric acid, boric acid, and sodium 
hexametaphosphate (SHMP). Glutaraldehyde and epichlorohydrin are not 
considered safe due to their toxic and irritant nature, which can entail hazardous 
accidents during the experiments. On the other hand, organic acids such as 

---