Wood mechanical densification: a review on processing

As a renewable and low-price material, wood has been used extensively in the construction, furniture and other fields. However, the mechanical strength of most wood species is moderate or low, which cannot meet the need of some advanced engineering structures and applications. High-strength wood resources are scarce and usually expensive. Therefore, it is of great significance for economic and sustainable development to improve mechanical properties of medium or low-density wood. Mechanical densification process is considered an effective method to improve wood mechanical properties. Compared with chemical methods, it has great advantages of preserving the eco-friendly characteristics of nature wood and environmental protection. Many researches and technologies of wood mechanical densification have been reported and attempted. This study summarized, classified and compared the different mechanical densification processes according to their commonality and individuality. The characteristics and disadvantages of different processes were also discussed and analyzed with a purpose of inspiring researchers and entrepreneurs to ameliorate the technologies.