Structural engineering of polyurethane coatings for high performance applications

Recent developments in the chemistry of halogen-free flame retardant polymers

Thermal stability and flame retardancy of polyurethanes

Anionic polymerizations of 2-methoxyethyl methacrylate (1), 2-(2-methoxyethoxy)ethyl methacrylate (2), and 2-[2-(2-methoxyethoxy)ethoxy]ethyl methacrylate (3) were carried out with 1,1-diphenyl-3-methylpentyllithium/lithium chloride and diphenylmethylpotassium/diethylzinc in THF at −78 °C for 2−4 h. The resulting polymers possessed the predicted molecular weights based on the molar ratios between monomers to initiators and the narrow molecular weight distributions (Mw/Mn < 1.1). The stability of the propagating chain ends of poly(2) and poly(3) was confirmed by the quantitative efficiency in the reversible sequential block copolymerizations between 2 and 3. New block copolymers having well-defined chain structures, poly(2)-block-poly(3), poly(3)-block-poly(2), polystyrene-block-poly(1), polystyrene-block-poly(2), and polystyrene-block-poly(3), were anionically synthesized. Both the solubility and the cloud point of polymers strongly depended on the length of hydrophilic oligo(ethylene glycol) unit. Poly(2...

Synthesis of Thermally Sensitive Water-Soluble Polymethacrylates by Living Anionic Polymerizations of Oligo(ethylene glycol) Methyl Ether Methacrylates

Effect of fibre surface modification on water-sorption characteristics of oil palm fibres

This review presents research in the area of polymeric coatings developed for protecting low earth orbit (LEO) space structures from atomic oxygen. Following a brief description of the LEO environment, ground-based simulation facilities for atomic oxygen and evaluation of protective coatings are discussed. Atomic oxygen resistant coatings based on different polymeric systems such as fluorinated polymers, silicones, poly (carborane-siloxane)s and decarborane-based polymers are presented. Finally, the performances of different coating systems are compared and the scope for further research to improve the performance of some of the coating systems is discussed.

Atomic oxygen resistant coatings for low earth orbit space structures

Studies on the thermal stability of natural rubber/polystyrene interpenetrating polymer networks: thermogravimetric analysis

Anionic polymerization of 4-(tert-butyldimethylsilyloxy)styrene (2) was investigated under high vacuum conditions (≈ 10−6 mbar). 2 was readily polymerized by lithium naphthalide to form a “living polymer” at −78°C. By subsequent acid hydrolysis of the resulting polymer, a linear, nearly monodisperse polymer of 4-vinylphenol of known molecular weight was obtained. Block copolymers of 2 with α-methylstyrene were also prepared by means of this living system.

Polymerization of monomers containing functional groups protected by trialkylsilyl groups, 4. Studies on anionic living polymerization of 4‐(tert‐butyldimethylsilyloxy)styrene

In present study, partially allyl-substituted hydridopolycarbosilane (5 mol% allyl) [AHPCS] has been characterized by spectral techniques and thermal analysis. The DSC studies show that, the polymer is self-cross-linking at lower temperatures without any incorporation of cross-linking agents. The spectral and thermal characterizations carried out at different processing stages indicate the possibility of extensive structural rearrangement accompanied by the loss of hydrogen and other reactions of C and Si containing species resulting in the conversion of the branched chain segment into a 3D SiC network structure. AHPCS gave ceramic residue of 72% and 70% at 900 and 1500 °C respectively in argon atmosphere. XRD pattern of 1500 °C heat-treated AHPCS, indicates the formation of silicon carbide with the particle size of 3–4 nm. AHPCS was used as matrix resin for the preparation of C/SiC composite without any interfacial coating over the T-300 carbon fabric reinforcement. Flexural strength value of 74–86 MPa for C/SiC specimen with density of 1.7 g/cm 3 was obtained after four infiltration and pyrolysis cycles.

S. Packirisamy

Papers

Atomic oxygen resistant coatings for low earth orbit space structures

Studies on the thermal stability of natural rubber/polystyrene interpenetrating polymer networks: thermogravimetric analysis

Polymerization of monomers containing functional groups protected by trialkylsilyl groups, 4. Studies on anionic living polymerization of 4‐(tert‐butyldimethylsilyloxy)styrene

Allylhydridopolycarbosilane (AHPCS) as matrix resin for C/SiC ceramic matrix composites

Transport of styrene monomer through natural rubber