A rigid foam comprising the reaction product of an (poly)isocyanate, and a polyethercarbonate polyol copolymer is described. The polyethercarbonate polyol copolymer is derived from the copolymerisation of one or more epoxides with CO.sub.2, wherein the total CO.sub.2 content of the polyethercarbonate polyol copolymer is between 1 and 40 wt %, the carbonate linkages are <95% of the total linkages from the copolymerisation, and the molecular weight is between 100 to 5000 g/mol. The foam is a polyurethane foam, more typically, a polyisocyanurate or a mixed polyisocyanurate/polyurethane foam. Methods, polyols and compositions for producing the foams are also described.

In some aspects, the present disclosure provides systems for forming hydrogels that comprise (i) a reactive multi-arm polymer that comprises three or more polymer arms linked to a core region, each arm comprising a polyether segment and a reactive moiety comprising a cyclic imide carboxy-C.sub.1-C.sub.6-alkyl ester end group or each arm comprising a polyether segment and a reactive moiety comprising a C.sub.2-C.sub.6-isocyanoalkyl end group and (ii) a polyamino compound comprising at least two amino (NH.sub.2) groups, wherein the reactive multi-arm polymer and the polyamino compound react to form a crosslinked hydrogel that does not contain ester groups and has long-term stability in vivo. In some aspects, the present disclosure provides methods of treatment using such systems and hydrolysis-resistant crosslinked hydrogels formed from such systems.

An example of a bottlebrush polymer has a polymer backbone and a plurality of individual brush moieties bonded to the polymer backbone. The individual brush moieties respectively include a crosslinked oxyamine moiety, a hydrophilic segment, and a surface adhesive terminal group.

It is provided a method of treatment of a human or animal patient in need thereof to achieve a reduction of the viscosity of mucus of the patient which is carried out by administering a polyglycerol derivative having a linear or dendritic polyglycerol backbone and carrying at least one thiol group covalently bound to the polyglycerol backbone. It is further provided a method of treatment of a human or animal patient suffering from chronic sinusitis, asthma, chronic bronchitis, cystic fibrosis, chronic obstructive pulmonary disease, emphysema, bronchiectasis, chronic inflammatory bowel diseases, constipation, gastrointestinal malabsorption syndrome, irritable bowel syndrome, steatorrhea or diarrhea by administering a polyglycerol derivative. Further specific thiol-functionalized polyglycerol derivatives and a corresponding manufacturing method are provided.