何謂 「生物可降解塑膠」？ 生物塑膠的原料來自植物或微 生物可再生的生物物質（如澱粉、 纖維素、蛋白質等），而非不可再 生的石油，大幅降低了碳排放，並 注入綠色基因，體現極佳的環保特 性。而且微生物能完全分解生物可 降解塑膠製成品，最終轉化為二氧 化碳和水，達致環保生活。 與傳統塑膠分別 生物可降解塑膠是一種能夠在 自然環境中被微生物分解成水、 二氧化碳和有機物的塑膠材料。與 傳統塑膠不同，生物可降解塑膠具 有更快的分解速度和更低的環境影 響。 1. 原材料 生物可降解塑膠原材料選用可 再生的物質，例如玉米澱粉、甘蔗 纖維素、乳酸、糖類等。而傳統塑 膠的原材料是石油和天然氣，通常 透過鑽探開採，然後運送到煉油廠 進行提煉。 2. 製造過程 生物可降解塑膠須經過化學聚 合反應過程，將物質分子轉化為高 分子的聚合物。常見的生物可降解 的高聚合物有聚乳酸（PLA）和聚羥 基烷酸酯（PHA）等。傳統塑膠須經 過提煉的石油或天然氣進行化學處 理，將其轉化為塑膠的基本成分， 如聚乙烯、聚丙烯、聚氯乙烯等。 3. 聚合工序 在生物可降解塑膠中，在生物 可降解的聚合物中加入添加劑， 以增加形成塑膠的能力；並將不同 的聚合物混合，形成塑料的複合材 料，經過擠壓、注塑、壓延等加 工工序，成為需要的生物可降解塑 膠製成品。而在傳統塑膠中，將 單一分子連接成長鏈分子，形成塑 膠聚合物；又將聚合物通過吹塑、 壓延、射出成型工序進行加工，製 造成各種形狀和尺寸的塑膠製品， 還有需要添加助劑，如穩定劑、染 料、填充劑等，以提升塑膠的性能 和外觀。 4. 棄置處理 生物可降解塑膠可埋入泥土， 泥土會分泌出細菌或真菌等微生 物，它們會進一步分解這些塑膠製 成品為小分子；塑膠的表面出現細 小裂縫和孔洞，當中塑膠的大分子 逐步被水分和酶降解為小分子；細 菌和真菌等微生物又會進一步分解 小分子；最終塑膠被完全分解為二 氧化碳、甲烷和水無機小分子，重 新進入自然物質循環。反之，傳統 塑膠如果埋在泥土裏，長久都不會 被分解，若焚燒，更會釋放出有毒 氣體。 因此傳統塑膠在原材料或棄置 過程都會破壞環境，又不能被環境 所吸收。反之，生物可降解塑膠可 被泥土中的微生物分解，將其焚燒 又不會產生毒氣，可見這種生物可 降解塑膠製成的產品更能親近環境。 生活應用及不足 隨着人們對環境保護的日益重 視，生物可降解塑料正成為備受關 注的新興材料。我們可看到一些企 業應用生物可降解塑膠製造產品。 例如日常使用的產品、食用工 具，或兒童的玩具，都使用生物可 降解塑膠。當中有汽水公司和連鎖 快餐店已經採用生物可降解塑膠， 製造他們的可樂瓶或汽水用的吸管 和咖啡奶茶使用的攪拌棒。清潔用 品公司使用甘蔗、木纖維或玉米澱 粉包裝產品。有連鎖傢俬公司的餐 飲部，使用木纖維和玉米澱粉製成 的餐具，這些餐具可完全讓泥土分 解。而這些塑膠產品對環境有積 極正面的影響，解決環保問題， 所以就算這些塑膠的價格高昂 一點，我們都應該多使 用對環境有益處 的生物可降解塑 膠產品。 生產成本高 雖然生物可降解塑膠能紓 緩傳統塑膠帶來的環境壓力， 可是生產成本很高，比傳 統塑膠高，增加企業的成本。消費 者看到成本高的生物可降解塑膠， 接受程度亦會下降。而且很多消費 者對生物可降解塑膠的認知不高， 眼看價格高昂的生物可降解塑膠產 品自然會卻步，選擇其他較便宜的 工具，或傳統塑膠製成品。 回收與堆肥 另外，生物可降解塑膠需要企 業繼續研發來提升性能，並須解 決生物可降解塑膠在回收和堆肥過 程中的問題。另外，生物可降解塑 膠原料的供給有限，原料供應也不 算穩定；同時須建立回收和堆肥系 統，以確保生物可降解塑膠得到正 確處理。 雖然生物可降 解 塑 膠 有 利 於 環 保 ， 但 尚處於發展 初期，企業須 克服成本和技術問 題，並讓消費者認識其 好處，選擇價格高的生物可 降解塑膠取代傳統塑膠， 以保護這片土地，令下一 代生活環境可更舒適。 小思考，大智慧 1.生物可降解塑膠相比減少使用塑 膠（走塑）更環保？ 2.生物可降解塑膠的發展，會否對 現有傳統塑膠產業造成威脅？ 參考答案 1.生物塑膠生產和回收利用過程中 的環境負擔，超過了節省的塑料 污染，則減少使用塑膠可能更環 保。若就防治污染和資源利用方 面，生物塑膠則具有明顯優勢； 而從環保效果而言，單純减少塑 料使用會更突出。因此，我們需 要從生命周期角度對比分析，評 估具體情況下兩種方式的環境 影響，綜合考慮才可得出更準確 結論。無論如何，減塑和使用生 物可降解塑膠都是重要的環保舉 措，未來可能需要結合運用兩種 方式，共同解決塑料污染問題。 2.生物可降解塑膠確實可能對傳統 塑膠行業產生一定衝擊，但更多 的應該是互補協同的關係。傳統 塑膠行業可以通過研發技術提高 其環保性，而生物可降解塑膠亦 需要傳統塑膠行業的技術支撐。 未來，石油基和生物基塑膠應該 能夠在不同應用場景中相互取長 補短，共同推動塑膠產業的綠色 轉型。 星島教室 生物科技與環保 鄭家寶博士 中華基督教會 蒙黃花沃紀念小學校長、 教育評議會副主席 周偉強博士 中華基督教會 蒙黃花沃紀念小學老師 作者介紹 塑膠污染已成為當代社會面 臨的巨大環境挑戰。傳統的塑膠 產品由石油製成，難以降解，長 期滯留在環境中，嚴重破壞生態 系統。過去10年，科學家們致 力解決這個問題，成功研製新興 的「生物可降解塑膠」。顧名思 義，相關產品可在泥土中分解， 解決環保問題。從生物可降解塑 膠的誕生，可看到人類環保生活 方式的改變。 本欄逢周四刊登，由教育評 議會邀請資深中小學老師、校長 及大學講師撰稿，旨在為學生提 供多元化的STEAM學習材料，引 發學生探求知識的興趣，將學習 融入生活，培養學生的世界觀、 敏銳的觸覺、積極學習的態度。 讀社論學 英文 Subscription for a new batch of silver bonds began on September 30, coinciding with the resurgence of the Hong Kong and mainland stock markets. The elderly, however, were not deterred. After all, they do not have the same risk appetite as young investors. With the prolonged slump in the stock market, the elderly are more focused on low-risk stable investment returns. On the first day of sale, several banks reported enthusiastic response, with some elderly individuals queuing up early to hand in their applications. Online subscriptions were also quite good. The number of subscribers and amount of money were both higher than last year. New records are expected. Foreign funds turn optimistic Silver bonds have been popular because the Hong Kong stock market underperformed over the past four years, leading to many investors becoming conservative. They seek more stable investment tools, with silver bonds undoubtedly being the best option. As the Fed has initiated a rate-cutting cycle, Hong Kong banks will follow suit, meaning that interest rates will gradually decline. Silver bonds allow holders to lock in at least a four per cent interest rate for the next three years plus the government guarantee of 100 per cent redemption at face value before maturation along with corresponding interest. Silver bonds thus become a zero-risk stable investment tool. In a global environment of decl ining interest rates, a bond yield of four per cent is quite attractive. However, the silver bond launch coincided with the resurgence of the Hong Kong and mainland stock markets with funds flocking crazily. Prices of mainland property stocks sometimes rose by 20 to 80 per cent in a single day. This raised concerns that investors might shift to stocks instead of buying bonds, which will affect sales. However, after over four years of a sluggish market, every time stock prices surged, experts would claim that it had bottomed, but each surge was always short-lived with a quick reversal. This led many investors to understand that stock prices can rise and fall fast which poses significant risks and makes them wary of chasing stocks at high prices. Most of those eligible to buy silver bonds are elderly with lower risk tolerance who seek stable returns. So they are not easily swayed by the recent surge. However, it is different from the brief surges in previous years, as it is supported by recordbreaking trading volumes. Since the Fed rate cut on September 19, it has increased from $148.8 billion to a record-breaking $445.7 billion last Friday. A new record of $505.8 billion was set on September 30. The Hang Seng Index has risen a total of 19.66 per cent in just eight trading days, equivalent to the 24 per cent gain in the first nine trading days. A-shares have also seen a similar situation, with trading volumes in the Shanghai and Shenzhen stock markets increasing from about 490 billion yuan on September 19 to a recordbreaking 2.59 trillion on September 30. With the influx of funds, the Shanghai Composite Index rose a total of 22.8 per cent over eight trading days. The scale of fund inf lux this t ime is unprecedented because the Fed has initiated a ratecutting cycle, providing room for Beijing to ease monetary and fiscal policies to rescue the property and stock markets. Even though the relevant measures have not yet been fully implemented, the market believes that it is determined to stabilize growth and the property & stock markets, which increases confidence and prompts funds to keep pouring in, especially so for those of foreign that were pessimistic. Seeing Beijing's strong monetary easing, they quickly turned optimistic and actively participated leading to a boom in both markets. Mainlanders hold stocks over long holiday A rebounce in confidence can also be reflected in investors holding stocks over the long holiday. The National Day Golden Week starts today. The Shanghai and Shenzhen stock markets will be closed until October 7. In the past, mainland investors used to sell stocks before long holidays. Trading was thus sparse just before holidays. However, this time it is completely the opposite, with total volume in the Shanghai and Shenzhen stock markets breaking records at 2.59 trillion yuan. Northbound funds broke the record at 208.7 billion, with a net purchase of 12.1 billion worth of Hong Kong stocks. Some investors even requested that the market remain open during the holiday, reflecting their optimism and wish not to miss out on this rare opportunity for substantial returns. As investors anticipate more rescue measures from Beijing, they tend to bet on the Hong Kong and mainland stock markets without hedging against the downside risks. The sentiment has become increasingly exuberant. Investors, however, have no crystal balls. They cannot predict the peak of this rising wave. The participants in this market rally with higher risk tolerance and quicker reactions are willing to chase profits. But elderly individuals will still be better off with silver bonds. 翻譯自10月1日《星島日報》社論 （http://std.stheadline.com/） subscription (n) —— 認購 resurgence (n) —— 復活 slump (n) —— 蕭條 conservative (adj) —— 保守的 redemption (n) —— 贖回 maturation (n) —— 到期 short-lived (adj) —— 短暫的 sway (v) —— 搖擺 risk appetite —— 風險胃納 rate-cutting cycle —— 減息周期 face value —— 原價 risk tolerance —— 風險容忍度 The proceeds from silver bonds will be directed to the Capital Works Reserve Fund to support various infrastructure projects, including the second phase of the Hung Shui Kiu/Ha Tsuen New Development Area in the Northern Metropolis. Financial Secretary Paul Chan Mo-po said that elderly citizens who subscribe to silver bonds will not only receive stable interest income but also contribute to the development of Hong Kong's infrastructure. 1. The word _____ in the first paragraph is the opposite of "surge". 2. Silver bonds have been popular because the Hong Kong _____ market was not doing well. 3. In the passage, the word _____ means "brief". 4. Mainland investors used to _____ stocks before long holidays. 5. According to the last paragraph, silver bonds are still a better choice for the _____. Answers 1. slump 2. stock 3. short-lived 4. sell 5. elderly & Q A Vocabulary Useful Terms Did you know? Silver bonds in "big era" assess risk 翻譯︰George D6 侷芎 02.28.2025 星期五
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