Carbinol (Hydroxyl) Terminated Polydimethylsiloxane, Mw 7000 - 8000

Catalog	ACM120359071-1
CAS	120359-07-1
Synonyms	2-Oxepanone, Polymer With Octamethylcyclotetrasiloxane;(Dimethylsiloxane)-(Caprolactone) Block Copolymer, Carbinolterminated; Carbinol(Hydroxyl)Terminated Polydimethylsiloxanecaprolactone Block Polymer
Molecular Weight	7000-8000
Boiling Point	> 205 °C
Melting Point	80 - 85 °C
Flash Point	> 110 °C
Appearance	Translucent granular powder
Relative Density	1.05

Case Study

Thermal Insulation and Stability of Polysiloxane Foams Containing Hydroxy-Terminated Polydimethylsiloxane

Zhang, Chunyu, et al. RSC advances, 2018, 8(18), 9901-9909.

Hydroxy-terminated polydimethylsiloxane (OH-PDMS) serves as the foundational component of polysiloxane foams (SIFs). This study enhanced SIF thermal insulation and stability by modulating OH-PDMS chain length, preparing a series of foams with varied cross-linking densities via foaming and cross-linking.
Synthesis of SIFs
OH-PDMS (25 g) was combined in a vessel with a platinum catalyst, vinyl-terminated PDMS, and foaming agent YQ-100 (1 g). Each component underwent 30-minute ultrasonic dispersion after addition. Polymethylhydrosiloxane (PMHS, 5 g) was finally added. Thorough mixing triggered extensive foam growth within 5-10 minutes. Samples were then fully cured at 105°C. Five OH-PDMS variants of differing chain lengths formed matrices for S1-S5 foams.
Key Findings
Longer OH-PDMS chains reduced average cell size from 932 μm to 220 μm and increased cell density from 4.92 × 10⁶ to 1.64 × 10⁸ cells/cm³. This significantly improved thermal insulation, with long-chain OH-PDMS achieving minimal thermal conductivity (0.077 W/m/K). Reduced cell size and elevated cell density primarily enabled lower thermal conductivity. Enhanced thermal stability stemmed from restricted polysiloxane chain mobility and increased network cross-linking density.

Hydroxyl-Terminated Polydimethylsiloxane for the Synthesis of Intrinsically Flame-Retardant Thermoplastic Polyimide-Urethane

Tang, Qiheng, et al. Industrial & Engineering Chemistry Research, 2014, 53(23), 9714-9720.

A novel series of intrinsically flame-retardant thermoplastic poly(imide-urethanes) (TPIUs) was synthesized using 4,4'-diphenylmethane diisocyanate (MDI), poly(tetrahydrofuran) (PTMG), pyromellitic anhydride (PMDA), and hydroxyl-terminated poly(dimethylsiloxane) (PDMS) as a flame retardant.
Synthesis
TPIUs were prepared via two-step polymerization. The melted MDI underwent a reaction with PTMG and PDMS at 80°C for one hour during mechanical agitation. After dissolving PMDA as the chain extender in DMF, the mixture underwent rigorous stirring for 12 hours while nitrogen gas was passed through it. The product was cast into a PTFE mold and underwent stepped drying (40°C/48h then 70°C to constant weight) to evaporate DMF. Reagent mole ratios for TPIU/PDMS variants are provided in Table 1.
Performance
TPIU/PDMS composites exhibit tensile strength of 17.5-29.77 MPa and elongation at break of 694-828%, meeting engineering requirements. TGA analysis shows comparable T5% and Tmax to pure TPIU, with marginally increased residue. Cone calorimetry confirms PDMS enhances flame retardancy: TPIU/12.4%PDMS shows 8.0% lower THR and 26.3% reduced p-HRR versus pure TPIU. SEM/FTIR/EDXS analysis of char residues identifies protective Si-O networks forming a physical barrier that inhibits further combustion.

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