Glass fiber-reinforced polymer liquid

ELASTIC MODULI OF GLASS FIBER-REINFORCED POLYMER LIQUID CRYSTALS... 

Li Youbing, Shi Wen, Li Jingyuan, et al. Structure and properties of glass fiber reinforced polypropylene/liquid crystal polymer blends. J. Macromol. Sci. Part B. 54 no. 9 (2015) 1144-1152. 

The most common way to functionalize the surface of sihca materials is to use silanes [28]. Silanes have been used for many years to modify the surface chemistry of dry silica materials, which are used in completely different areas such as glass-fiber-reinforced polymers [29] and liquid chromatography [30]. Especially in the field of high performance liquid chromatography (HPLC), there are numerous papers on how to surface modify porous sihca by using various silanes [28-32]. 

Some of the common types of plastics that are used are thermoplastics, such as poly(phenylene sulfide) (PPS) (see POLYMERS CONTAINING SULFUR), nylons, liquid crystal polymer (LCP), the polyesters (qv) such as polyesters that are 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diallyl phthalate and phenolic resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials are available in several variations which have a range of physical properties. 

As mentioned earlier, suspensions of particulate rods or fibers are almost always non-Brownian. Such fiber suspensions are important precursors to composite materials that use fiber inclusions as mechanical reinforcement agents or as modifiers of thermal, electrical, or dielectrical properties. A common example is that of glass-fiber-reinforced composites, in which the matrix is a thermoplastic or a thermosetting polymer (Darlington et al. 1977). Fiber suspensions are also important in the pulp and paper industry. These materials are often molded, cast, or coated in the liquid suspension state, and the flow properties of the suspension are therefore relevant to the final composite properties. Especially important is the distribution of fiber orientations, which controls transport properties in the composite. There have been many experimental and theoretical studies of the flow properties of fibrous suspensions, which have been reviewed by Ganani and Powell (1985) and by Zimsak et al. (1994). 

Arikan, A. Kaynak, C. Tincer, T. Influence of liquid elastomeric additive on the behavior of short glass fiber reinforced epoxy. Polym. Compos. 2002, 23, 790. 

Fig. 4.163 Flexural-creep modulus of glass fiber reinforced liquid-crystal polymer at different temperatures and stress levels [12Els].

A fibril can be defined as a structural entity with material properties that are biased predominantly along a linear dimension or symmetry axis [51]. Such morphological entities are the reinforcing elements in MFCs. Furthermore, in contrast to the common short glass fiber reinforced composites or polymer-polymer composites where the reinforcement represents a liquid crystalline polymer, in the case of MFCs, flexible-chain polymers are used as reinforcement as emphasized above. 

Ozel [86] studied the abrasive wear behavior of liquid crystal polymer, 30% reinforced polyamide 4,6, and 30% glass fiber-reinforced polyphenylene sulfide engineering polymers at atmospheric conditions. Pin-on-disc arrangement wear tests were carried out at 1 m/s test speed and load values of 4,6, and 8 N. Test durations were for 50,100 m and 150 m sliding distances. 

The specific wear rates of liquid crystalline polymers, 30% glass fiber-reinforced polyamide 4,6, and 30% glass fiber-reinforced polyphenylene sulfide ranged from 3 X 10" to 4.43 X 10- mmVNm, 1.63 x 10 to 1.1 x 10 mm /Nm, and 2.4 x 10 to 2.1 X 10" mmWm, respectively. 

General discussions of the effect of reinforcing agents on the thermal properties of polymers include glass fiber-reinforced polyethylene terephthalate [28], multiwalled carbon nanotube-reinforced liquid crystalline polymer [29], polysesquioxane [30, 31], polynrethane [31], epoxy resins [32], polyethylene [33], montmorillonite clay-reinforced polypropylene [34], polyethylene [35], polylactic acid [36, 37], calcium carbonate-filled low-density polyethylene [38], and barium sulfate-filled polyethylene [39]. 

In addition, plastics behave differently under simultaneous mechanical load [243]. The attack mechanisms function entirely differently in plastics than they do in metals. The intramolecular secondary valence bonds (van der Waals forces) are several orders of magnitude smaller (1/100 to 1/1000) in polymers than in metals. Therefore, the free volume between bulky and entangled molecular chains is so large that the comparatively small gas and liquid molecules can easily diffuse into the intermediate spaces and become embedded there. Thus, the influence on the plastic is not limited to its surface, but takes place virtually throughout its volume. In glass fiber-reinforced plastics with their heterogeneous structure, interfacial problems also develop [243]. 

Figure 13.22 Tracking resistance and breakdown voltage of bulk samples of glass fiber-reinforced engineering plasties. TCP liquid crystal polymer UL Underwriters Laboratories.

Figure 14.4 Capillary rheology of 30% glass fiber-reinforced SPS versus 30% glass fiber-reinforced liquid crystalline polymer (LCP),poly(l,4cyclohexamethylene tere-phthalate) (PCI), and polybutylene terephthalate (PBT). All resins were tested 50°C above their melting point.

A liquid crystalline polymer contains rigid rod like structure as discussed earlier which forms the hquid crystal phases. This rod like molecular conformations and chain stiffness give LCPs their most important self-reinforcing properties that are close to that of glass fiber reinforced composites. 

Epoxy resin systems with fiber reinforcements are called "reinforced systems" or "composites." Composites are made by impregnating reinforcing fibers such as glass, synthetic polymer, or graphite fibers, by one of several processes with the desired epoxy resin system, and then curing in a heated mold or die. Epoxy composite systems are formulated with either liquid or solid resins with selection of the type of system dependent on the fabrication process, the cure temperature, and the final part application. 

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