As a new type of biodegradable material, polybutylene adipate terephthalate (PBAT) is mainly used in agricultural film and food packaging. However, compared with ordinary plastics, PBAT has problems such as poor crystallinity, low melt strength and high price, which limit its application in the field of fiber and membrane materials. Therefore, PBAT needs to be modified, mainly by blending modification and Mainly for chain extension and modification, in order to achieve the purpose of reducing costs and improving its overall performance.
Blending modification of PBAT and degradable polymer materials
1.Blending modification of PBAT and PHBV
PHBV is a kind of biopolymer polyester with good biocompatibility, biodegradability and bioabsorbability, but is brittle and difficult to process and shape. Blending and modifying PBAT and PHBV can not only accelerate the degradation of PBAT, but also improve the overall performance of PHBV.
2.Blending modification of PBAT and PPC
PPC, also known as polymethyl ethylene carbonate, is an environmentally friendly polymer that is non-toxic and has good biodegradability. Studies have shown that blending PPC and PBAT can not only continue the good biodegradability, but also improve the comprehensive performance of the composite material.
3.Blending modification of PBAT and PBS
The processing performance of PBS is poor, and it is difficult to use the general methods of plastic processing for blow molding and casting. Usually PBAT and PBS are blended and modified to improve the processing performance of PBS and increase its melt strength.
4.Blending modification of PBAT and PLA
The tensile strength and modulus of PBAT are low. PLA has the characteristics of high strength and high modulus. However, due to its inherent brittleness, low elongation at break, low impact strength, and easy bending deformation, etc., PBAT is combined with PLA blending improves the toughness of the material while maintaining the degradation performance of the material.
Blending modification of PBAT and natural polymer materials
1.Blending modification of PBAT and starch
Starch has a wide range of sources, is cheap, and can be completely biodegradable, but it does not have thermoplasticity, is easy to absorb water, and is difficult to process. Adding modified starch to the PBAT matrix can greatly reduce the cost and accelerate the degradation rate of PBAT to reduce costs and Solve the problems of resource shortage and environmental pollution.
2.Blending modification of PBAT and cellulose
Cellulose is a natural material with a wide range of sources, low price, low density, high toughness, and degradable. However, cellulose is a polyhydroxy compound and has a certain degree of hydrophilicity. If it is directly blended with hydrophobic polyester, it will Phase separation occurs. Therefore, when using cellulose-modified PBAT, it is necessary to modify the cellulose
3.Blending modification of PBAT and modified lignin
Using lignosulfonic acid (LS) and MA grafted product (MLS) as fillers, PBAT/LS and PBAT/MLS composites were prepared by melt blending method. The results show that, compared with LS, MLS and PBAT have better dispersibility, compatibility and thermal stability when blended. With the increase of MLS content, the melting crystallization temperature of the composite material first rises and then decreases, and the tensile strength and elongation at break of the composite material first increase and then decrease. Considering the overall filling amount and mechanical properties, the best ratio is m(MLS):m(PBAT)= 10:90. At this time, the tensile strength increases by 10.0%, and the elongation at break increases by 29.1%.
PBAT and inorganic filling modification
1.Montmorillonite filled modified PBAT
Montmorillonite is a kind of layered silicate with abundant source, low price, certain expansion performance and large surface area. The layered structure endows montmorillonite with certain functions, which makes the prepared composite materials have mechanical properties and thermal properties. Performance and barrier performance have been greatly improved.
2.CaCO3 filled modified PBAT
Nano-CaCO3 has the characteristics of small particle size and high activity, and has a strong interfacial binding force with polymers. It is usually used as a filler in different polymers. Therefore, adding it to PBAT to prepare degradable composite materials can improve the performance of PBAT and greatly reduce the cost.
3.Organic nano-clay filled modified PBAT
Nanoclay is a kind of silicate mineral with unique layer or flake shape. The unique structure can make the polymer easy to be filled in, so it has become a nano material widely used for filling modified polymers. Adding a small amount of nanoclay (mass fraction 3% to 5%) to the polymer can make the composite material obtain good mechanical properties, thermal stability and dimensional stability, and the special layer structure of the clay can make the composite material have a certain The barrier properties.
4. CNTs modified PBAT
As a reinforcing material with excellent mechanical properties, toughness, electrical conductivity and thermal conductivity, CNTs modified PBAT to broaden the application fields of PBAT.
5.Blending of diphenols and PBAT to improve processing performance
Due to the different structures of diphenols small molecule compounds, the addition of diphenols small molecule compounds to PBAT can inhibit crystallization and reduce the crystallization rate and crystallinity of PBAT; the melt viscosity and energy storage of PBAT after modification The modulus and loss modulus have decreased, indicating that adding diphenolic small molecule compounds can improve the processing performance of PBAT
The combined use of PBAT with degradable materials and inorganic fillers can not only improve the processing performance of PBAT and reduce production costs, meet the needs of practical applications, but also broaden its scope and field of application.
