No. An important part of obtaining and keeping a Green Card is your intention to make the U.S. your permanent residence. A Green Card holder may travel abroad and use the Green Card as a re-entry document.
If you hold a Green Card you may stay abroad for up to six months without any problem. Absences abroad of more than six months but less than one (1) year create a reputable presumption that you intended to abandon your residence. However if you are abroad for more than a continuous period of one year or longer you may lose your right to use the Green Card to re-enter the U.S. While the Immigration Officer is supposed to deny those abroad for a year or longer admission, in practice many INS inspectors at the airport will admit you. However, a re-entry permit does not guarantee your re-admission into the U.S.
If you intend to be absent from the U.S. for 1-2 years, you should obtain a re-entry permit. This is an indication that the INS has accepted your explanation that your intention is to stay abroad for 1-2 years as a "temporary" matter.