i need a list of atleast 20 research chemicle vendors who are in the u.s.a or ship to the u.s.a

Here is a list of research chemical vendors that either operate within the U.S. or ship to the U.S.:

**Sigma-Aldrich** (part of Merck KGaA) - A widely known supplier of chemicals for various research applications.
   
**Thermo Fisher Scientific** - Offers a range of chemicals and lab supplies for research.

**Fisher Scientific** - A large distributor of laboratory supplies, including research chemicals.

**VWR** - A global supplier of laboratory products and chemicals.

**Alfa Aesar** (part of Thermo Fisher Scientific) - Specializes in scientific research materials and chemicals.

**Acros Organics** - Offers high-quality organics and fine chemicals for research.

**TCI America** - Provides a wide range of research chemicals and reagents.

**Biorad Laboratories** - Supplies reagents and chemicals for biological research.

**Santa Cruz Biotechnology** - Offers various biochemicals and research reagents.

**MP Biomedicals** - A supplier of chemicals for life sciences and biomedical research.

**BioVision** - Provides a variety of biochemical products for research purposes.

**Cayman Chemical** - Specializes in providing research chemicals and biochemicals, especially in the fields of immunology, neuroscience, and biochemistry.

**ChemSpider** - An online database for chemical compounds that links to suppliers.

**American Sigma** - A supplier of fine chemicals and reagents.

**Strem Chemicals** - Offers specialty chemicals for research and development.

**Chemicals and Reagents** - Provides a broad selection of chemicals for laboratory use.

**Sapphire Bioscience** - Supplies biochemicals and reagents for life sciences.

**Aldrich Chemical Company** - Offers a comprehensive range of fine chemicals for research.

**Thermo Scientific** - Part of Thermo Fisher Scientific that specializes in providing a wide range of research chemicals.

**LabChem** - Supplies a variety of laboratory chemicals and reagents.

Before making any purchases, it's advisable to verify the vendor's reputation, shipping practices, and product availability. Always adhere to local regulations regarding the purchase and handling of chemicals.