Polycarbonate Chemical Compatibility Chart

Polycarbonate is highly resistant to many chemicals, making it a popular choice for applications where durability and chemical resistance are required. It performs well with:

• Acids: It is compatible with many acids and acid salt solutions.
• Oxidizing/Reducing Agents: It resists both oxidizers and reducers.
• Saline Solutions: Neutral and acid salt solutions do not typically affect polycarbonate.
• Greases, Oils, and Detergents: It stands up well to many common lubricants and cleaning agents.
• Hydrocarbons: Saturated, aliphatic, and cycloaliphatic hydrocarbons, as well as most alcohols, are generally compatible.

Additional beneficial properties include:

• High Melting Point: Around 288°C (550°F), allowing for high-temperature applications.
• Autoclavability: Suitable for sterilization processes.
• Thermoplastic Behavior: It can be melted, cooled, and reheated without significant degradation.
• Superior Impact Resistance: Offers excellent toughness and durability.

However, polycarbonate is not compatible with certain chemicals, including:

• Solvents: Methyl alcohol, acetone, ketones, and ethers can attack polycarbonate.
• Hydrocarbons: Aromatic and chlorinated hydrocarbons are detrimental.
• Alkaline Solutions: Both aqueous and alcoholic alkaline solutions can cause damage.
• Ammonia Gas: Exposure may compromise its integrity.

Here is a useful chart for chemical compatibility of polycarbonate:

Ratings: Chemical Effect
A = Perfect - Ideal for long term contact
B = Good, Minor Effect, slight corrosion or discoloration - not for storage
C = Minorly compatible. Softening, loss of strength, or swelling may occur. Limit contact.
D = Incompatible, not recommended for ANY use.
N/A = Information not available.

Footnotes:
^1. OK to 72°F (22°C)
^2. OK to 120°F (48°C)

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If you are interested in the organic chemistry of polycarbonates read on. 

Polycarbonate is a high-performance thermoplastic whose unique properties arise from its well-defined organic polymer structure. Synthesized from bisphenol-A and phosgene, polycarbonate consists of repeating units characterized by aromatic rings bridged by carbonate linkages. These structural features impart rigidity, thermal stability, and distinct reactivity profiles that are central to its chemical behavior.

At the molecular level, the backbone of polycarbonate comprises alternating phenylene and carbonate groups. The phenylene moieties, derived from bisphenol-A, are electron-rich aromatic systems that contribute to the overall conjugation and provide significant mechanical strength and thermal resistance. In contrast, the carbonate group (–O–(C=O)–O–) is a polar ester-like linkage that, despite its inherent stability, is susceptible to nucleophilic attack under alkaline conditions. 

Under mildly acidic conditions, the electrophilic nature of the carbonyl carbon in the carbonate linkage is partially shielded by resonance stabilization from the adjacent aromatic rings. This results in a decreased reactivity toward protonation and minimizes the extent of acid-catalyzed hydrolysis. However, in strongly basic media, the nucleophilic hydroxide ion can attack the electrophilic carbonyl carbon, initiating a hydrolytic cleavage of the polymer chain. The mechanism involves the formation of a tetrahedral intermediate that subsequently collapses, leading to chain scission and degradation of the polycarbonate matrix.

The solvent interactions of polycarbonate are also governed by its organic chemistry. Its moderate polarity, attributed to the carbonate groups, allows for selective solvation by polar protic solvents. Solvents such as acetone and methyl ethyl ketone can disrupt interchain interactions through dipolar interactions and hydrogen bonding, thereby lowering the cohesive energy density of the polymer. This phenomenon explains the susceptibility of polycarbonate to stress cracking and embrittlement in the presence of such solvents. In contrast, non-polar aliphatic hydrocarbons are less effective at solvating the polar carbonate moieties, which accounts for the observed chemical resistance in these environments.

Thermal stability in polycarbonate is a direct consequence of its aromatic content. The delocalized π-electron system within the phenylene rings distributes thermal energy effectively, which contributes to its high melting point (approximately 288°C or 550°F) and excellent resistance to thermal oxidation. The carbonate linkage, while polar, is also relatively robust due to the resonance stabilization provided by the adjacent oxygen atoms. This stability under high temperature conditions permits polycarbonate to be processed via techniques such as injection molding and autoclaving without significant degradation.

The interchain interactions in polycarbonate are mediated by both van der Waals forces and weak hydrogen bonds involving the carbonate oxygen atoms. These interactions create a semi-crystalline morphology that is responsible for its excellent impact resistance. The interplay between the rigid aromatic segments and the more flexible carbonate linkages enables polycarbonate to absorb and dissipate energy effectively under mechanical stress.