Starch-containing thermoplastic or elastomer compositions, and method for preparing such compositions

A thermoplastic or elastomeric composition comprising:

• at least 50% by weight and at most 99.95% by weight of an amylaceous composition (a) comprising at least one starch,
• at least 0.05% by weight and at most 50% by weight of a nanometric product (b) consisting of particles having at least one dimension of between 0.1 and 500 nanometers and selected from the group consisting of:
• products formed of mixtures based on at least one lamellar clay and on at least one cationic oligomer,
• organic, inorganic or mixed nanotubes,
• organic, inorganic or mixed nanocrystals and nanocrystallites,
• organic, inorganic or mixed nanobeads and nanospheres which are separate, in bunches or agglomerated, and
• any mixture of at least two of these nanometric products, these percentages being expressed by dry weight and with respect to the sum, by dry weight, of (a) and (b), and
• at least one nonamylaceous polymer (c).

A thermoplastic or elastomeric composition, comprising:

• from 25 to 85% by weight of at least one starch,
• from 8 to 40% by weight of at least one starch plasticizer, other than water,
• from 2 to 40% by weight of a nanometric product (b) consisting of particles having at least one dimension of between 0.1 and 500 nanometers and selected from the group consisting of:
• products formed of mixtures based on at least one lamellar clay and on at least one cationic oligomer,
• organic, inorganic or mixed nanotubes,
• organic, inorganic or mixed nanocrystals and nanocrystallites,
• organic, inorganic or mixed nanobeads and nanospheres which are separate, in bunches or agglomerated,
• and the mixtures of at least two of these nanometric products, and
• from 5 to 60% by weight of at least one nonamylaceous polymer (c),
• these percentages being expressed by dry weight and with respect to the total dry weight of the thermoplastic or elastomeric composition.