**7. References**


**8** 

*Poland* 

**The Effect of Concentration and** 

**Properties of Cellulose Acetate** 

*The Poznan University of Economics, Poznań*

Patrycja Wojciechowska

**Type of Plasticizer on the Mechanical** 

**Butyrate Organic-Inorganic Hybrids** 

Organic/inorganic polymer hybrids is a rapidly growing area of research because they offer opportunities to combine desirable properties of organic polymers (toughness, elasticity, formability) with those of inorganic solids (hardness, chemical resistance, strength). There are several routes to prepare hybrid materials, but one of the most common method is solgel technique generating inorganic phase within organic polymer matrix. The advantage of sol–gel technique is mild processing characteristics and the possibility of tailoring morphology of the growing inorganic phase and thus properties of the material by the subtle control of various reaction conditions. This process includes hydrolysis of the precursor (metal alkoxide) followed by condensation reactions of the resulting hydroxyl groups. Considering the nature of the interface between the organic and inorganic phases, hybrid materials can be categorized into two different classes. The first class corresponds to non-covalently bound networks of inorganic and organic phases. These hybrids show weak interactions between the polymer matrix and inorganic phase, such as van der Waals, hydrogen bonding or weak electrostatic interactions and can be prepared by physical mixing of an organic polymer with a metal alkoxide. In the second class organic and inorganic phases are linked through strong chemical bonds (covalent or ionic). Chemical bonding can be achieved by the incorporation of silane coupling groups into organic

Cellulose has received a great deal of attention in recent decades as a substitute for petrochemical based polymers. Natural polymer shows however some limitations, for instance with regard to poor processability or high water absorbency. Cellulose esters such as cellulose acetate (CA), cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) are less hydrophilic than cellulose, thermoplastic materials [4]. To improve their processability and mechanical properties, the addition of plasticizers is usable. Plasticizers as polymer additives serve to decrease the intermolecular forces between the polymer chains, resulting in a softened and flexible polymeric matrix. They increase the polymer's elongation and enhance processability by lowering the melting and softening points and

**1. Introduction** 

polymers [1-3].

viscosity of the melts [5].

