松香是由多种树脂酸组成，其化学性质决定于树脂酸所能产生的各种反应。树脂酸分子具有两个化学反应中心，即双键和羧基。由于树脂酸的双键反应和羧基反应，使松香易于异构化，对空气的氧化作用比较敏感，并具有加成、歧化、氢化、聚合、氨解、酯化、成盐、脱羧 等反应。利用这些反应，可以将松香加以改性，制成一系列的改性松香，提高松香的使用价值。如利用歧化反应，可生产歧化松香；利用聚合反应，可生产聚合松香；利用氢化反应，可生产氢化松香；利用加成反应，可生产出马来松香等等。这些松香的改性产品，性质稳定，在各种工业中的应用更为广泛。

Rosin, also called colophony or Greek pitch (Latin:pix græca), is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term "colophony" comes from colophonia resina, Latin for "resin from Colophon," an ancient Ionic city.