degradation generally requires harsh and strictly controlled conditions. [5,8,9] Moreover, the number of plastic types that are capable of being fully and efficiently degraded by such methods is very less. Therefore, the most effective approach to solve the issue of plastic waste accumulation consists in substituting traditional plastics with novel plastics that can be fully degraded into environmentally friendly substances in natural environments. [10-18] Poly(lactic acid) (PLA) can be degraded into CO 2 and H 2 O by microorganisms under specific and controlled humidity and temperature conditions. [16,19,20] Currently, degradable PLA is widely used in biomedical equipment, food packaging, and disposable tableware. [16] Nevertheless, to meet a wide range of applications, the development of new types of degradable plastics remains crucial. [10,14,21] In particular, it is necessary to develop plastics that are capable of complete degradation under natural environmental conditions. Poly(vinyl alcohol) (PVA) production is cost-effective, and the material itself possesses desirable degradability, nontoxicity, high tensile strength, and excellent flexibility. [11,22-26] In natural environments, PVA can be fully degraded into CO 2 and H 2 O by microorganisms through the oxidation of PVA hydroxyl groups into diketones and the subsequent hydrolysis of carbon-carbon diketone bonds. [11,22,27,28] Therefore, PVA-based plastics are environmentally friendly and degradable, and they can be used for a wide range of potential applications. [29,30] PVA-based plastics have been fabricated by complexation of PVA with partner species such as inorganic nanofillers, [31] organic molecules, [32] and polymers [25,30] containing complementary noncovalent interactions. However, because of the water solubility of PVA, these PVA-based plastics absorb water from the environment and exhibit lower mechanical strength compared to those of PEbased plastics in watery environments. This limitation restricts the applications of PVA-based plastics and increases their storage cost. Commercially available poly(vinyl formal) (PVF) and poly(vinyl butyral) (PVB), which are synthesized via an acid-catalyzed acetal reaction between the PVA hydroxyl groups and the aldehyde groups of formaldehyde and n-butyraldehyde, respectively, exhibit good water resistance. However, PVF and PVB are difficult to be degraded in soil because of their high acetalization ratios (usually higher than ≈70%). [33,34] Therefore, it is necessary to fabricate PVA-based degradable plastics that can maintain sufficiently high mechanical strength in watery