Polymer pollution from nonbiodegradable polymer blends is a source of increasing environmental concern. The obvious solution, the replacement of petroleum-based polymers with biodegradable polymers from renewable sources, is difficult, since these polymers are highly immiscible. Here, we show how the addition of only a few percent of a tertiary phase can enable compatibilization and enhancement of the mechanical properties. The tertiary phase can be selected for any binary polymer system using the spreading coefficient (λ ij ) and the work of adhesion (W a ) as guides. We demonstrate this method using poly(lactic acid) as the continuous matrix phase, styrenic polymers, polystyrene (PS) or high-impact polystyrene (HIPS), as the discontinuous minority phase, and styrene acrylic copolymers [styrene methyl methacrylate (SMMA)] as the tertiary phase. We show that a distinct maximum in the impact toughness, nearly 58 and 56% for PS and HIPS blends, respectively, occurs when only 1.2 and 1.5% SMMA copolymers are added.

The three lowest full three-dimensional adiabatic and three diabatic global potential energy surfaces are reported for the title system. The accurate ab initio method (MCSCF/MRCI) with larger basis sets (aug-cc-pVQZ) is used to reduce the adiabatic potential energies, and the global adiabatic potential energy surfaces are deduced by a three-dimensional B-spline fitting method. The conical intersections and the mixing angles between the lowest three adiabatic potential energy surfaces are precisely studied. The most possible nonadiabatic reaction pathways are predicted, i.e., N( 2 D) + H 2 (X 1 ∑ g + ) → NH 2 (2 2 A′) → CI (1 2 A′–2 2 A′) → NH 2 (1 2 A′) → CI (1 2 A″–1 2 A′) → NH 2 (1 2 A″) → NH(X 3 ∑ – ) + H( 2 S). The products of the first excited state (NH(a 1 Δ) + H( 2 S)) and the second excited state (NH(b 1 ∑ g + ) + H( 2 S)) can be generated in these nonadiabatic reaction pathways too.

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The adiabatic potential energies for the lowest three states of a Li2H system are calculated with a high level ab initio method (MCSCF/MRCI) with a large basis set.