export and import all the permissions on schema objects within a database SQL Server 2008 Is it possible to export all the users roles and their permissions on schema objects within a database in a .sql file and import them later in an other database ?
There are a couple of answers to a similar question that might be of use to you.

How to export all the security-related information from a SQL Server database

The answer I believe is yes. You can use SSMS to generate scripts and have it filtered to just users.

Here is a webpage detailing how you would Create Script to Copy Database Schema and All The Objects.