The amount of plastic waste increases every year and the time, required for its biodegradation, is still unknown. PHB has attracted much attention in recent years, because it is an environmentally friendly polymer. PHB is a fully biodegradable polyester, is optically active, piezoelectric, and is very low permeable to O2, CO2 and H2O. PHB is a partially crystalline thermoplastic and has a high melting point, high degree of crystallinity and has mechanical properties like those of PP but it is stiff and brittle. The brittleness depends on the degree of crystallinity, glass temperature and microstructure. Solves this problem by a new blends and new results achieve in polymer physics and applications in polymer science. The new blends have good mechanical properties like a fracture stress (25-18 MPa), elongation (400-660%), good impact strength, better elasticity and long term stability in comparison to be PE, PP. PHB is mixed with biodegradable additives like nucleates, plasticizers and lubricants. The Addition of nucleation leads to formation of small spherulites with smaller diameters, which have necessary the mechanical properties. The blends’ spherulites grow banded spherulites (above 100 °C as a spiral with twisting lamellae like PE, PPO, and PVDF) and non-banded spherulites under 90°C non-banded spherulites form as a fibrous texture as in PP and PEO. By adding plasticizers, the glass temperature shifts to lower value of 20°C to -50°C, which improves the mechanical properties. Only one glass temperature was detected for the blends below the glass temperature of PHB. The additives have improved processing properties.