Soft-resin polymers

Medium molar mass polyisobutenes are obtained by using higher purity isobutene, by lowering the temperature to — -25 to -40° C, and eventually by operating in the presence of a chain-terminating agent (diisobutenes) [12]. The semiliquid or soft-resin polymers present typical Mv in the range 40-85 103 (M = 8-13-103). 

The polyvinylethers form a further group of thermoplastics which are not used as containers or packaging films. They are atactic polymers forming oils, sticky soft resins or nonsticky rubber elastic materials according to their molecular weight and composition. All polyvinylethers are very resistant to saponification by dilute acids and alkalis. They can subsequently be used as unsaponifiable polymer plasticizers and for the manufacture of glues. 

Figure 13. Forms of damage of specimens repaired using of (a) epoxy resin Sikadur 53, (b) hard flexible polymer PT and (c) soft flexible polymer PM...

Soft-templating has been recently reported by the same group, where CNCs were embedded into an amino resin polymer. The obtained composite films were highly flexible and their colouration could be permanently changed by simply applying pressure. 

The foregoing Desmacoll polymers show compatibility with some or all of the following polymers to the extent that they give clear solutions and films phthalic resins (Soft Resin MM, Alkydal BG), xylene-formaldehyde resin, cyclohexanone-formaldehyde resin (Synthetic Resin AFS), highly chlorinated terphenyl (Clo-phen Resin A60), teipene-phenolic resin (Durez 12603), acetyl cellulose (Cellit BL700), nitrocellulose, Desmocolls 12 and 22, nitrile rubber (Perbunan N), post chlorinated PVC (Rheno-flex), vinyl chloride-vinyl acetate copolymer (Vinnol), rosin esters (Pentalin A, Stabelite Ester 10), and coumarone resin. 

The metal parts of the injection molder, ie, the liner, torpedo, and nozzle, that contact the hot molten resin must be of the noncatalytic type to prevent accelerated decomposition of the polymer. In addition, they must be resistant to corrosion by HCl. Iron, copper, and zinc are catalytic to the decomposition and caimot be used, even as components of alloys. Magnesium is noncatalytic but is subject to corrosive attack, as is chromium when used as plating. Nickel alloys such as Duranickel, HasteUoy B, and HasteUoy C are recommended as constmction materials for injection-molding metal parts. These and pure nickel are noncatalytic and corrosion-resistant however, pure nickel is rather soft and is not recommended. 

The minimum service temperature is determined primarily by the Tg of the soft phase component. Thus the SBS materials ctm be used down towards the Tg of the polybutadiene phase, approaching -100°C. Where polyethers have been used as the soft phase in polyurethane, polyamide or polyester, the soft phase Tg is about -60°C, whilst the polyester polyurethanes will typically be limited to a minimum temperature of about 0°C. The thermoplastic polyolefin rubbers, using ethylene-propylene materials for the soft phase, have similar minimum temperatures to the polyether-based polymers. Such minimum temperatures can also be affected by the presence of plasticisers, including mineral oils, and by resins if these become incorporated into the soft phase. It should, perhaps, be added that if the polymer component of the soft phase was crystallisable, then the higher would also affect the minimum service temperature, this depending on the level of crystallinity. 

Both hard and soft carbons are used as negative electrode materials for lithium-ion batteries. Hard carbon is made by heat-treating organic polymer materials such as phenol resin. The heat-treatment tempera-... 

Poly(trimethylene terephthalate) (PTT) is a polymer with very useful properties. As a textile fibre it has excellent softness, stretch and recovery. As a resin it has excellent barrier properties. Developed over 60 years ago, PTT has not been very widely used compared to poly(ethylene terephthalate) (PET) as one of the key monomers 1,3-propanediol (PDO) has been expensive. 

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