A large amount of plastic waste is hardly recycled and still remains in landfills in our environment. This situation might cause environmental problems and make it difficult to find space available for discarding additional disposal waste. As demand for solving global problems, the development of renewable, degradable, and recyclable materials, such as a composite of polycaprolactone (PCL) and agricultural byproducts, have been pursued in recent years. However, the compatibility between them is too low due to the hydrophilic and hydrophobic properties. In this study, a maleated polymer is improved for better compatibility between them with a focus on the optimum maleated concentration for the grafted polymer: PCL-g-MA.