Modifiers matching rubber:

• soft,
• natural,
• hard,
• organic,
• conventional,
• resilient,
• thermoset,
• stock,
• porous,
• raw,
• inexpensive,
• reliable,
• softer,
• ordinary,
• elastic,
• special,
• conductive,
• expensive,
• liquid,
• polar,

Simple categories matching polar:

• group,
• polymer,
• compound,
• macromolecule,
• drug,
• reagent,
• adhesive,
• nutrient,
• base,
• solute,
• fluid,
• lubricant,
• solvent,
• substance,
• animal,
• protein,
• region,
• atom,
• reactant,
• impurity,
• activator,
• material,
• plastic,
• ligand,
• constituent,
• dielectric,
• metabolite,
• rubber,
• bird,
• structure,
• liquid,
• substrate,
• lipid,
• molecule,
• moiety,
• residue,
• mammal,
• resin,
• pesticide,
• organism,
• contamination,
• monomer,
• solid,
• insulator,
• oil,
• sorbent,
• derivative,
• intermediate,
• diluent,
• elastomer,
• radical,
• metal,
• volatile,
• unit,
• surface,
• medium,
• gas,
• fauna,
• particle,
• portion,
• fiber,
• fraction,
• component,
• bond,
• contaminant,
• chemical,
• hormone,