The main characters in A Raisin in the Sun all undergo some changes, but the minor characters are largely static.
Walter, Ruth, Mama (Lena), and Beneatha all change in certain ways. They are dynamic characters in that regard, although this is not always obvious at various points in the action.
Walter, although an adult man, married, and a father, seems immature through most of the play. He is so fixated on achieving his personal goals that he forgets his role in the family, and allows his frustration to come out in anger and disrespect to his wife and mother. At the end, after he realizes he has set himself up to be robbed, and then supports the move to the house, it seems like he will turn a corner and become a mature adult.
Ruth also changes in her attitude toward family and their situation. Early in the play, she is so despondent over their poverty and lack of opportunities that she contemplates having an abortion. The good news of their move to a lovely home helps her focus on a positive future.
Mama, almost a stereotype for most of the play, turns out to be very dynamic. She is the one who takes the bold plunge to buy a house in an all-white neighborhood, where they will be pioneers in integrating. This step seems out of character, but viewers are left suspecting she had previously hidden many of her personal inner resources.
Beneatha also changes in that she is first involved with George, a conventional but dull young man, but pushes him away when she realizes how he is patronizing her because she is female. We are left not knowing where her new interest in African cultures, symbolized by Asagai and by her cutting her hair into a natural, will take her.
George and Asagai function largely as generic boyfriends, two opposite types with whom Beneatha can interact. Travis is a typical young boy and is not seen changing. Walter's friend Bobo, who figures in the action largely as a messenger, is also flat.