The chemical modification methods are composed of acid-or alkaline hydrolysis, acetylation, hydroxylation, acetylation and hydroxylation, hydrogenation, sulfonation, ethylene oxidation and so on.

• 化学改性方法主要包括酸碱水解法、乙酰化法、羟基化法、羟酰化法、氢化法、磺化法、乙氧基改性法等。