產(chǎn)品詳情
聚苯乙烯玻璃化溫度80~90℃,非晶態(tài)密度1.04~1.06克/立方厘米,晶體密度1.11~1.12克/立方厘米,熔融溫度240℃,電阻率為1020~1022歐·厘米。導(dǎo)熱系數(shù)30℃時(shí)0.116瓦/(米·開(kāi))。通常的聚苯乙烯為非晶態(tài)無(wú)規(guī)聚合物,具有優(yōu)良的絕熱、絕緣和透明性,長(zhǎng)期使用溫度0~70℃,但脆,低溫易開(kāi)裂。此外還有全同和間同以及無(wú)規(guī)立構(gòu)聚苯乙烯。全同聚合物有高度結(jié)晶性,間同聚合物有部分結(jié)晶性。
STYRON GPPS 650 HF 盛禧奧南經(jīng)銷(xiāo)商代理 分類(lèi)
聚苯乙烯(PS)包括普通聚苯乙烯,發(fā)泡聚苯乙烯(EPS),高抗沖聚苯乙烯(HIPS)及間規(guī)聚苯乙烯(SPS)。普通聚苯乙烯樹(shù)脂,無(wú)臭,無(wú)色的透明顆粒,似玻璃狀脆性材料,其制品具有極高的透明度,透光率可達(dá)90%以上,電絕緣性能好,易著色,加工流動(dòng)性好,剛性好及耐化學(xué)腐蝕性好等。普通聚苯乙烯的不足之處在于性脆,沖擊強(qiáng)度低,易出現(xiàn)應(yīng)力開(kāi)裂,耐熱性差及不耐沸水等。
屬性
普通聚苯乙烯樹(shù)脂屬無(wú)定形高分子聚合物,聚苯乙烯大分子鏈的側(cè)基為苯環(huán),大體積側(cè)基為苯環(huán)的無(wú)規(guī)排列決定了聚苯乙烯的物理化學(xué)性質(zhì),如透明度高.剛度大.玻璃化溫度高,性脆等??砂l(fā)性聚苯乙烯為在普通聚苯乙烯中浸漬低沸點(diǎn)的物理發(fā)泡劑制成,加工過(guò)程中受熱發(fā)泡,專(zhuān)用于制作泡沫塑料產(chǎn)品。高抗沖聚苯乙烯為苯乙烯和丁二烯的共聚物,丁二烯為分散相,提高了材料的沖擊強(qiáng)度,但產(chǎn)品不透明。間規(guī)聚苯乙烯為間同結(jié)構(gòu),采用茂金屬催化劑生產(chǎn),發(fā)展的聚苯乙烯新品種,性能好,屬于工程塑料。
STYRON GPPS 650 HF 盛禧奧華南經(jīng)銷(xiāo)商華南代理成型性能
無(wú)定形料,吸濕小,不須充分干燥,不易分解,但熱膨脹系數(shù)大,易產(chǎn)生內(nèi)應(yīng)力。流動(dòng)性較好,可用螺桿或柱塞式注射機(jī)成型。宜用高料溫,高模溫,低注射壓力,延長(zhǎng)注射時(shí)間有利于降低內(nèi)應(yīng)力,防止縮孔、變形.。 可用各種形式澆口,澆口與塑件圓弧連接,以免去處澆口時(shí)損壞塑件。脫模斜度大,頂出均勻。塑件壁厚均勻,不帶鑲件,如有鑲件應(yīng)預(yù)熱。
1.吸水性極小,成型前可不干燥。模溫30-60度,料溫140-200度。
2.性脆易裂,熱膨脹系數(shù)大,易產(chǎn)生內(nèi)應(yīng)力。
3.流動(dòng)性較好,應(yīng)注意模具間隙,防止縮孔、飛邊。
4.宜采用高料溫、高模溫、低注射壓力,延長(zhǎng)注射時(shí)間有利于降低內(nèi)應(yīng)力,防止縮孔、變形,但料溫過(guò)高,容易出現(xiàn)銀絲,料溫低或脫模劑多則透明性差。
5.可采用各種形式的澆口,脫模斜度宜大,頂出力均勻,以防開(kāi)裂。
6.塑件壁厚均勻,不帶嵌件,各面應(yīng)圓弧連接,不宜有缺口、尖角。
we are introduced to the narrator, a pilot, and his ideas about grown-ups
Once when I was six years old I saw a magnificent picture in a book, called True Stories from Nature, about the primb forest. It was a picture of a boa constrictor in the act of swallowing an animal. Here is a copy of the drawing.
In the book it said: "Boa constrictors swallow their prey whole, without chewing it. After that they are not able to move, and they sleep through the six months that they need for digestion."
I pondered deeply, then, over the adventures of the jungle. And after some work with a colored pencil I succeeded in making my first drawing. My Drawing Number One. It looked like this:
I showed my masterpiece to the grown-ups, and asked them whether the drawing frightened them.
But they answered: "Frighten? Why should any one be frightened by a hat?"