Biodegradable polymers, while eco-friendly, come with several drawbacks. Firstly, their degradation rate is highly dependent on environmental conditions such as temperature, humidity, and microbial activity, leading to inconsistent decomposition times. In industrial composting facilities, they might break down adequately, but in landfills or natural environments, they often degrade slowly, similar to traditional plastics. Secondly, these materials can be more expensive to produce due to the complex manufacturing processes and sourcing of raw materials. This higher cost can be prohibitive for some industries, limiting widespread adoption. Thirdly, there are concerns about the practicality and efficiency of recycling biodegradable polymers alongside conventional plastics, complicating waste management systems. Lastly, some biodegradable polymers release harmful substances during degradation, posing risks to ecosystems if not managed properly.

No, PVC is not a metal. PVC stands for Polyvinic Chloride, which is a synthetic thermoplastic material made from polymerizing vinyl chloride. PVC is widely used in construction for pipes, in healthcare for medical devices, in the automotive industry, and for home goods due to its durability, resistance to corrosion, and low cost. Unlike metals, PVC is characterized by its plastic properties including being a poor conductor of electricity, flexibility, and resistance to oxidation and degradation by acids or alkalis. Metals, on the other hand, are generally good conductors of electricity and heat, have a shiny appearance, and can oxidize, forming rust in the case of iron, for example. PVC's versatility and cost-effectiveness make it a popular alternative to metal in many applications where metal's specific properties are not required.

A strong metal. titanium is ideal for aerospace. medical. military. and other industries due to its high strength-to-weight ratio. corrosion resistance. and high temperature resistance.